31 (number)
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|---|---|---|---|---|
| Cardinal | thirty-one | |||
| Ordinal | 31st (thirty-first) | |||
| Factorization | prime | |||
| Prime | 11th | |||
| Divisors | 1, 31 | |||
| Greek numeral | ΛΑ´ | |||
| Roman numeral | XXXI, xxxi | |||
| Binary | 111112 | |||
| Ternary | 10113 | |||
| Senary | 516 | |||
| Octal | 378 | |||
| Duodecimal | 2712 | |||
| Hexadecimal | 1F16 | |||
31 (thirty-one) is the natural number following 30 and preceding 32. It is a prime number.
Mathematics
[edit]31 is a prime number, a twin prime[1] (with 29), and a Mersenne prime.[2]
In other fields
[edit]31 equal temperament is a popular microtonal tuning for musical instruments because it provides a good approximation of harmonic intervals.
January, March, May, July, August, October and December have 31 days.
California was the 31st state to join the United States.
31 is the international calling code for the Netherlands.
Notes
[edit]References
[edit]- ^ Sloane, N. J. A. (ed.). "Sequence A077800 (List of twin primes {p, p+2}.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2023-06-07.
- ^ Sloane, N. J. A. (ed.). "Sequence A000668 (Mersenne primes (primes of the form 2^n - 1).)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2023-06-07.
External links
[edit]
Look up thirty-one in Wiktionary, the free dictionary.
Wikimedia Commons has media related to 31 (number).
- Prime Curios! 31 from the Prime Pages
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