1872

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1872 < 1871 | 1873 >
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1872 is the number following 1871 and preceding 1873.

Properties

• Its factors are 1, 2, 3, 4, 6, 8, 9, 12, 13, 16, 18, 24, 26, 36, 39, 48, 52, 72, 78, 104, 117, 144, 156, 208, 234, 312, 468, 624, 936 and 1872, making it a composite number.
• 1872 is an even number .
• 1872 is an unhappy number.
  

• 1872 is abundant.
  
• Its prime factorization is 2⁴ × 3² × 13¹.
  
• 1872 is a Harshad number, meaning it is divisible by the sum of its digits.
  
• It is also:

1. First differences of A025475, powers of a prime but not prime.
2. Number of partitions of n-set into odd blocks.
3. Multiples of 18 containing a 18 in their decimal representation.
4. Numbers whose sum of prime indices is twice their number, counted with multiplicity in both cases.
5. Numbers that can be expressed as the difference of the squares of primes in just one distinct way.
6. Aliquot sequence starting at 276.
7. Norm of the sum of divisors function sigma(n) generalized for Gaussian integers.
8. Heinz numbers of connected graphical partitions.
9. Sum of the divisors of n-th triangular number.
10. Numbers n such that n is both the average of some twin prime pair p, q (q = p+2) (i.e., n = p+1 = q-1) and is also the average of the prime before p and the prime after q.
11. Unique sequence satisfying SumXOR_{d divides n} a(d) = n^2 for any n > 0, where SumXOR is the analog of summation under the binary XOR operation.
12. Numbers n such that fractional part of e^(Pi*sqrt(n)) > 0.99.

Approximations

Notation	Lower bound	Upper bound
Up-arrow notation	43 ↑ 2
Scientific notation	1.872 x 103	1.873 x 103
Slow-growing hierarchy	\(g_{\omega^{\omega}}(4)\)	\(g_{\omega^{\omega}}(5)\)
Copy notation	18[2]	19[2]
Chained arrow notation	43 → 2
Bowers' Exploding Array Function/Bird's array notation	{43,2}
Fast-growing hierarchy	f2(7)	f2(8)
Hardy hierarchy	Hω(936)	Hω(936)
Middle-growing hierarchy	m(ω,10)	m(ω,11)
Hyper-E notation	E3.2723
Hyper-E notation (non-10 base)	\(E[43]2\)
Hyperfactorial array notation	6!	7!
X-Sequence Hyper-Exponential Notation	43{1}2
Steinhaus-Moser Notation	4[3]	5[3]
PlantStar's Debut Notation	[1]	[2]
H* function	H(0)	H(0.1)
Bashicu matrix system with respect to version 4	(0)[43]	(0)[44]
m(n) map	m(1)(4)	m(1)(5)
s(n) map	\(s(1)(\lambda x . x+1)(935)\)	\(s(1)(\lambda x . x+1)(936)\)