91

91 < 90 | 92 >
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

91 (ninety-one) is a positive integer following 90 and preceding 92. Its ordinal form is written "ninety-first" or 91st.

Properties

91 is an odd composite number.

91 is the 13th triangular number, and therefore the number of tiles in a double-12 domino set.

In the Beklemishev's Worm function, a sequence starting with [1,0,1,0,1,1] will end in 91 steps to reach [], resulting in [1,0,1,0,1,1] being equal to 91.

In googology

In Greek-based number-naming systems, 91 is associated with prefix "henenneaconta-", and with prefix "unnonaginti-" in Latin systems.