18

18 < 17 | 19 >
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

18 (eighteen) is a positive integer following 17 and preceding 19. Its ordinal form is written "18th" or "eighteenth".

Properties

• 18 is an even composite number.
• 18 is a solitary number.
• 18 is the number for the French department of Cher.

In googology

In Greek-based number-naming systems, 18 is associated with prefix "octadeka-", and with prefix "octodeci-" in Latin systems. In the Misalian seximal system, this number is called "thirsy", because it's three times six.

DeepLineMadom calls the number zeroogolseptiplex and unoo-ool.

Cultural significance

Since it is also the age of majority in most countries, it is associated with adult-only media and the age of consent in much of America. It is one of few non-single-digit numbers that has its own emoji: 🔞

See also

• Quintillion, 10¹⁸ using the short scale