Number
991
991 is a prime, odd, a calendar year.
Properties
- Parity
- Odd
- Digit count
- 3
- Digit sum
- 19
- Digital root
- 1
- Palindrome
- No
- Divisor count
- 2
- σ(n) — sum of divisors
- 992
Primality
991 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Aliquot sum (sum of proper divisors):
1
Representations
- In words
- nine hundred ninety-one
- Ordinal
- 991st
- Roman numeral
- CMXCI
- Binary
- 1111011111
- Octal
- 1737
- Hexadecimal
- 3DF
Also seen as
Prime neighborhood
Unicode codepoint
ϟ
U+03DF
Lowercase letter (Ll)
UTF-8 encoding: CF 9F (2 bytes).
Hex color
#0003DF
RGB(0, 3, 223)
IPv4 address
As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.223.