Number
3
3 — Three
3 is a prime, odd, a calendar year.
Three is the second prime, the first odd prime, and the first Mersenne prime ((2^2 - 1)). It is also the second triangular number.
Properties
- Parity
- Odd
- Digit count
- 1
- Digit sum
- 3
- Digital root
- 3
- Palindrome
- Yes
- Divisor count
- 2
- σ(n) — sum of divisors
- 4
Primality
3 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Aliquot sum (sum of proper divisors):
1
Representations
- In words
- three
- Ordinal
- 3rd
- Roman numeral
- III
- Binary
- 11
- Octal
- 3
- Hexadecimal
- 3
Also seen as
Prime neighborhood
ASCII character
As an ASCII codepoint, 3 is control character (0x03). ASCII control character.
Hex color
#000003
RGB(0, 0, 3)
IPv4 address
As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.3.