Jump to content

91 (number)

From Wikipedia, the free encyclopedia
(Redirected from Number 91)
← 90 91 92 →
Cardinalninety-one
Ordinal91st
(ninety-first)
Factorization7 × 13
Divisors1, 7, 13, 91
Greek numeralϞΑ´
Roman numeralXCI
Binary10110112
Ternary101013
Senary2316
Octal1338
Duodecimal7712
Hexadecimal5B16

91 (ninety-one) is the natural number following 90 and preceding 92.

In mathematics

[edit]
91 as the sum and difference of two positive cubes

91 is:

The decimal equivalent of the fraction 191 can be obtained by using powers of 9.

In science

[edit]

In other fields

[edit]

Ninety-one is also:

References

[edit]
  1. ^ Sloane, N. J. A. (ed.). "Sequence A001358". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  2. ^ "Sloane's A000384 : Hexagonal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
  3. ^ "Sloane's A003215 : Hex (or centered hexagonal) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
  4. ^ "Sloane's A060544 : Centered 9-gonal (also known as nonagonal or enneagonal) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
  5. ^ "Sloane's A005898 : Centered cube numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
  6. ^ "Sloane's A000330 : Square pyramidal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
  7. ^ Sloane, N. J. A. (ed.). "Sequence A047696 (Smallest positive number that can be written in n ways as a sum of two (not necessarily positive) cubes.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  8. ^ Friedman, Erich. What's Special About This Number? Archived 2018-02-23 at the Wayback Machine
  9. ^ "Sloane's A005043 : Riordan numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
  10. ^ "John Conway proves that 91 is the smallest number which looks prime but isn't". Ryan Andersen. 31 December 2020. Retrieved 2024-05-09.
  11. ^ "Prime Numbers". 9 May 2024.