Number
7
7 — Seven
7 is a prime, odd, a calendar year.
Seven is the fourth prime number and the lowest natural number that cannot be represented as the sum of the squares of three integers. It appears repeatedly across cultures: seven days of the week, seven wonders of the ancient world, seven deadly sins.
Properties
- Parity
- Odd
- Digit count
- 1
- Digit sum
- 7
- Digital root
- 7
- Palindrome
- Yes
- Divisor count
- 2
- σ(n) — sum of divisors
- 8
Primality
7 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Aliquot sum (sum of proper divisors):
1
Representations
- In words
- seven
- Ordinal
- 7th
- Roman numeral
- VII
- Binary
- 111
- Octal
- 7
- Hexadecimal
- 7
Also seen as
Prime neighborhood
ASCII character
As an ASCII codepoint, 7 is BEL (bell). ASCII control character.
Hex color
#000007
RGB(0, 0, 7)
IPv4 address
As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.7.