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.

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.

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