Number
31
31 is a prime, odd, a calendar year.
Properties
- Parity
- Odd
- Digit count
- 2
- Digit sum
- 4
- Digital root
- 4
- Palindrome
- No
- Divisor count
- 2
- σ(n) — sum of divisors
- 32
Primality
31 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Aliquot sum (sum of proper divisors):
1
Representations
- In words
- thirty-one
- Ordinal
- 31st
- Roman numeral
- XXXI
- Binary
- 11111
- Octal
- 37
- Hexadecimal
- 1F
Also seen as
Prime neighborhood
ASCII character
As an ASCII codepoint, 31 is control character (0x1F). ASCII control character.
Hex color
#00001F
RGB(0, 0, 31)
IPv4 address
As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.31.