Number
661
661 is a prime, odd, a calendar year.
Properties
- Parity
- Odd
- Digit count
- 3
- Digit sum
- 13
- Digital root
- 4
- Palindrome
- No
- Divisor count
- 2
- σ(n) — sum of divisors
- 662
Primality
661 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Aliquot sum (sum of proper divisors):
1
Representations
- In words
- six hundred sixty-one
- Ordinal
- 661st
- Roman numeral
- DCLXI
- Binary
- 1010010101
- Octal
- 1225
- Hexadecimal
- 295
Also seen as
Prime neighborhood
Unicode codepoint
ʕ
U+0295
Lowercase letter (Ll)
UTF-8 encoding: CA 95 (2 bytes).
Hex color
#000295
RGB(0, 2, 149)
IPv4 address
As an unsigned 32-bit integer, this is the IPv4 address 0.0.2.149.