| 4 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Numbers 0 - 99 | |||||||||
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 |
| 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 |
| 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 |
| 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 |
| 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 |
| 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 |
| 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 |
| 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 |
| 90 | 91 | 92 | 93 | 94 | 95 | 96 | 97 | 98 | 99 |
4 (four) is a positive integer following 3 and preceding 5. Its ordinal form is written "4th" or "fourth".
Properties[]
Visualization of 4
- 4 is a composite number, and the first natural number with this property. 4 is an even square number. 4 is the 2nd tetrahedral number. 4 is the 2nd Busy Beaver number. 4 is the 2nd superperfect number. Plugging 2 into the hyper operators degenerates to 4: \(2 \uparrow\uparrow ... \uparrow\uparrow 2 = 4\).
- 4 is associated with bad luck in Eastern numerology because the Chinese word for "four" sounds similar to the word for "death."
- It is possible to test for divisibility by 4 in base 10 by looking at last 2 digits of the number. If the 2-digit number is divisible by 4, then the whole number is.
- Ignoring weekdays, the Julian calendar repeats every 4 years.
- Its Roman numeral is most commonly IV, but on clock faces, IIII is also used.
- Its prime factorization is 4 = 2².
- All known multiperfect numbers > 6 are divisible by 4.
- Base four, sometimes used as a way of compressing binary, is called quaternary.
In googology[]
- Some googologisms based on 4 are supertet, quadroogol and googolquadriplex. 4 can be thought as zeroth term of sequence defining Graham's number: \(g_0\) = 4.
- In Greek-based number naming systems, 4 is associated with prefix tetra-, and with prefix quadri- in Latin systems.
- 4 can be named gartwo, fztwo, fugatwo, megafugatwo, or boogatwo with the gar-, fz-, fuga-, megafuga-, and booga- prefixes respectively.
- Aarex Tiaokhiao coined the name binary-booiol or binary-golsol for this number, as s(2,100,1,2) = s(2,2,100,1) = s(2,2,100) in strong array notation.[1]
- Username5243 coined the names Binary-Goodol and Binary-Goonolplex for this number, and it's equal to 2[1]2 = 2[1]2[1]1 in Username5243's Array Notation.[2]
- HaydenTheGoogologist2009 coined the mane binary-goobol for this number, and it's equal to \(\{2,100(1)2\}\) in BEAF.[3]
Googological functions returning 4[]
- Rado's Sigma Function: \(\Sigma(2)=4\)
- Xi function: \(\Xi(4)=4\)
- Hyperfactorial: \(H(2)=4\)
- Factorexation: \(2\,\backslash=4\)
- Superfactorial: (Clifford Pickover): \(2\$=4\)
- Graham sequence: \(G_{0}\) = 4
Sources[]
- ↑ Part 1 (LAN) - Aarex Googology
- ↑ Part 1 - My Large Numbers
- ↑ Hayden's Big Numbers - Goobol series. Retrieved 2022-09-26.
Gar-: garone · gartwo · garthree · garfour · garfive · garsix · garseven · gareight · garnine · garten · garhundred · garmillion · gargoogol · gareceton · gartrialogue · gargoogolplex · gargiggol
Fz-: fzone · fztwo · fzthree · fzfour · fzfive · fzsix · fzseven · fzeight · fznine · fzten · fztwenty · fzthirty · fzhundred · fzthousand · fzmillion · fzgoogol · fzmilliplexion · fzgoogolplex · fzgargoogolplex · fzgiggol
Fuga-: fugaone · fugatwo · fugathree · fugafour · fugafive · fugasix · fugaseven · fugaeight · fuganine · fugaten · fugahundred · fugagoogol · fugagoogolplex · fugagargoogolplex · fugagiggol
Megafuga-: megafugaone · megafugatwo · megafugathree · megafugafour · megafugafive · megafugasix · megafugaseven · megafugaeight · megafuganine · megafugaten · megafugahundred · megafugagoogol · megafugagoogolplex · megafugagargoogolplex · megafugagargantugoogolplex · megafugagrangol
Extensions:
Booga-:: boogaone · boogatwo · boogathree · boogafour · boogafive · boogasix · boogaten · boogahundred · boogagoogol · boogagoogolplex
Gag-:: gagone · gagtwo · gagthree · gagfour · gagfive · gagsix · gagseven · gageight · gagnine · gagten · gaggoogol · gaggoogolplex
Googol Regiment
Niloogol · Niloogolplex · Niloogolduplex · Niloogoltriplex · Niloogolquadriplex · Niloogolquintiplex · Niloogolsextiplex · Niloogolseptiplex · Niloogoloctiplex · Niloogolnoniplex · Goonol · Goodol · Gootol · Gooquol · Gooqnol · Goosol · Goospol · Gooctol · Goonvol· Goodcol · Goovol · Gooqtol · Gootirol · Gooqrol · Goohfol · Gooxtol · Goostol · Gootgol · Goontol · Gooducol · Gooqnicol · Goomol · Goomyrol · Binary-Googol · Binary-Goonol · Binary-Goodol · Binary-Gootol · Binary-Gooquol · Binary-Gooqnol · Binary-Goovol · Binary-Gooqtol · Binary-Gootirol · Binary-Goohfol · Binary-Goomol · Binary-Goomyrol · Ternary-Googol · Ternary-Goonol · Ternary-Goodol · Ternary-Gooqnol · Ternary-Goodcol · Ternary-Gooqtol · Ternary-Goohfol · Ternary-Goomol · Ternary-Goomyrol · Quaternary-Googol · Quinary-Googol · Senary-Googol · Septary-Googol · Octal-Googol · Octal-Goonol · Octal-Goodol · Octal-Gooqnol · Octal-Goodcol · Octal-Gooqtol · Octal-Goohfol · Octal-Goomol · Octal-Goomyrol · Novary-Googol · Undecimal-Googol · Duodecimal-Googol · Hexadecimal-Googol · Hexadecimal-Goonol · Hexadecimal-Gooqnol · Hexadecimal-Goodcol · Hexadecimal-Goohfol · Hexadecimal-Goomol · Hexadecimal-Goomyrol · Vigesimal-Googol · Trigesimal-Googol · Sexagesimal-Googol · Googolnilex · Niloogolunex · Goonolplex · Goodolplex · Gootolplex · Gooquolplex · Gooqnolplex · Goosolplex · Goospolplex · Gooctolplex · Goonvolplex · Goodcolplex · Goovolplex · Gooqtolplex · Goohfolplex · Gooducolplex · Goomolplex · Goomyrolplex · Binary-Googolplex · Binary-Goonolplex · Binary-Gooqnolplex · Binary-Goodcolplex · Binary-Goohfolplex · Binary-Goomolplex · Ternary-Googolplex · Quaternary-Googolplex · Quinary-Googolplex · Octal-Googolplex · Duodecimal-Googolplex · Hexadecimal-Googolplex · Vigesimal-Googolplex · Sexagesimal-Googolplex · Googolduplex · Gooqnolduplex · Goodcolduplex · Goomolduplex · Goomyrolduplex · Binary-Googolduplex · Hexadecimal-Googolduplex · Googoltriplex · Goomoltriplex · Googolquadriplex · Googolquintiplex · Googolsextiplex · Googolseptiplex · Googoloctiplex · Googolnoniplex · Googoldeciplex
Doogol Regiment
Doogol · Doonol · Doodol · Dootol · Dooquol · Dooqnol · Doosol · Doospol · Dooctol · Doonvol · Doodcol · Doovol · Dooqtol · Dootrol · Dooqrol · Doohfol · Dooxtol · Doostol · Dootgol · Doontol · Dooducol · Dooqnicol · Doomol · Doomyrol · Binary-Doogol · Binary-Doonol · Binary-Doodol · Binary-Dootol · Binary-Dooquol · Binary-Dooqnol · Binary-Doodcol · Binary-Doovol · Binary-Doohfol · Binary-Doomol · Binary-Doomyrol · Ternary-Doonol · Ternary-Doodol · Ternary-Dooqnol · Ternary-Doodcol · Ternary-Doogol · Ternary-Doomol · Quaternary-Doogol · Quinary-Doogol · Octal-Doogol · Octal-Doonol · Octal-Dooqnol · Octal-Doodcol · Octal-Doomol · Duodecimal-Doogol · Hexadecimal-Doogol · Vigesimal-Doogol · Doogolunex · Doogolduunex · Doogoltriunex · Doogolquadriunex · Googolduex · Goonolduex · Goodolduex · Gooqnolduex · Goodcolduex · Goovolduex · Goohfolduex · Goomolduex · Goomyrolduex · Binary-Googolduex · Binary-Goodcolduex · Binary-Goomolduex · Ternary-Googolduex · Octal-Googolduex · Hexadecimal-Googolduex · Googolplexiduex · Gooqnolplexiduex · Goodcolplexiduex · Goomolplexiduex · Binary-Googolplexiduex · Googolduplexiduex · Goodcolduplexiduex · Googoltriplexiduex · Googolquadriplexiduex · Googolquintiplexiduex · Doogolplex · Doogolduex · Dooqnolplex · Doodcolplex · Doovolplex · Dooqtolplex · Doohfolplex · Doomolplex · Doomyrolplex · Binary-Doogolplex · Binary-Doodcolplex · Binary-Doomolplex · Ternary-Doogolplex · Octal-Doogolplex · Hexadecimal-Doogolplex · Googolduduex · Goodcolduduex · Goomolduduex · Binary-Googolduduex · Googolplexiduduex · Goodcolplexiduduex · Googolduplexiduduex · Googoltriplexiduduex · Googolquadriplexiduduex · Doogolduplex · Doodcolduplex · Doomolduplex · Doomyrolduplex · Binary-Doogolduplex · Googolplexitriduex · Googolduplexitriduex · Doogoltriplex · Googolquadriduex · Googolplexiquadriduex · Doogolquadriplex · Googolquintiduex · Doogolquintiplex · Doogolsextiplex · Doogolseptiplex · Doogoloctiplex · Doogolnoniplex · Doogoldeciplex
Toogol Regiment
Toogol · Toonol · Toodol · Tootol · Tooquol · Tooqnol · Toosol · Toospol · Tooctol · Toonvol · Toodcol · Toovol · Tooqtol · Tootrol · Tooqrol · Toohfol · Tooducol · Toomol · Toomyrol · Binary-Toogol · Binary-Toodol · Binary-Tootol · Binary-Tooquol · Binary-Tooqnol · Binary-Toodcol · Binary-Toohfol · Binary-Toomol · Ternary-Toogol · Ternary-Toodol · Ternary-Tooqnol · Ternary-Toodcol · Ternary-Toomol · Quaternary-Toogol · Octal-Toogol · Octal-Toodcol · Duodecimal-Toogol · Hexadecimal-Toogol · Toogolunex · Toogolduunex · Toogolduex · Toogolplexiduex · Toogolduexiplex · Toogolduduex · Googoltrex · Goonoltrex · Gooqnoltrex · Goodcoltrex · Goohfoltrex · Goomoltrex · Goomyroltrex · Binary-Googoltrex · Ternary-Googoltrex · Octal-Googoltrex · Hexadecimal-Googoltrex · Googolplexitrex · Goodcolplexitrex · Goomolplexitrex · Binary-Googolplexitrex · Googolduplexitrex · Googoltriplexitrex · Googolquadriplexitrex · Doogoltrex · Dooqnoltrex · Doodcoltrex · Doomoltrex · Doomyroltrex · Binary-Doogoltrex · Octal-Doogoltrex · Hexadecimal-Googoltrex · Googolduexitrex · Goodcolduexitrex · Goomolduexitrex · Binary-Googolduexitrex · Googolplexiduexitrex · Googolduplexiduexitrex · Doogolplexitrex · Doodcolplexitrex · Doomolplexitrex · Binary-Doogolplexitrex · Googolduduexitrex · Googolplexiduduexitrex · Doogolduplexitrex · Googoltriduexitrex · Doogoltriplexitrex · Doogolquadriplexitrex · Toogolplex · Toogoltrex · Toonolplex · Tooqnolplex · Toodcolplex · Toomolplex · Toomyrolplex · Binary-Toogolplex · Octal-Toogolplex · Googoldutrex · Goodcoldutrex · Googolplexidutrex · Googolduplexidutrex · Doogoldutrex · Doodcoldutrex · Googolduexidutrex · Doogolplexidutrex · Toogolduplex · Toodcolduplex · Toomolduplex · Binary-Toogolduplex · Googoltritrex · Googolplexitritrex · Doogoltritrex · Googoldexidutrex · Doogolplexitritrex · Toogoltriplex · Googolquadritrex · Doogolquadritrex · Toogolquadriplex · Toogolquintiplex · Toogolsextiplex · Toogolseptiplex · Toogoloctiplex · Toogolnoniplex · Toogoldeciplex
2-entry series
Linear series
Megoogol · Meg-Googol · Meg-Doogol · Meg-Kiloogol · Meg-Kil-Googol · Meg-Dukiloogol · Meg-Trukiloogol · Dumegoogol · Dumeg-Googol · Dumeg-Kiloogol · Dumeg-Dukiloogol · Trumegoogol · Trumeg-Kiloogol · Tetrumegoogol · Pentumegoogol · Gigoogol · Gig-Googol · Gig-Kiloogol · Gig-Megoogol · Dugigoogol · Trugigoogol · Teroogol · Duteroogol · Truteroogol · Petoogol · Ectoogol · Zettoogol · Yottoogol · Xennoogol · Wekoogol
Two-row series
Linoogol · Lin-Googol · Lin-Doogol · Lin-Kiloogol · Lin-Megoogol · Lin-Gigoogol · Dulinoogol · Dulin-Googol · Trulinoogol · Kilulinoogol · Kilulin-Googol · Kilulin-Linoogol · Kilulin-Dulinoogol · Dukilulinoogol · Megulinoogol · Megulin-Kilulinoogol · Dumegulinoogol · Gigulinoogol · Terulinoogol · Petulinoogol · Ectulinoogol · Zettulinoogol · Yottulinoogol · Xennulinoogol · Wekulinoogol
Note: The readers should be careful that numbers defined by Username5243's Array Notation are ill-defined as explained in Username5243's Array Notation#Issues. So, when an article refers to a number defined by the notation, it actually refers to an intended value, not an actual value itself (for example, a[c]b = \(a \uparrow^c b\) in arrow notation). In addition, even if the notation is ill-defined, a class category should be based on an intended value when listed, not an actual value itself, as it is not hard to fix all the issues from the original definition, hence it should not be removed.