odd, prime, palindrome · 7th positive integer
The number 7
7 is an odd prime number. It's known as often considered the luckiest number, the days of the week, the colors of the rainbow. It is the 7th positive integer.
Quick reference
| Prime factorization | 7 (prime) |
| Divisors | 1, 7 |
| Binary | 111 |
| Hexadecimal | 0x7 |
| Roman numeral | VII |
| Digit sum | 7 |
| Properties | odd, prime, palindrome |
Why 7 is notable
Often considered the luckiest number, the days of the week, the colors of the rainbow.
Frequently asked
Is 7 a prime number?
Yes. 7 is prime — its only divisors are 1 and itself.
What are the factors of 7?
The factors (divisors) of 7 are 1, 7.
What is 7 in binary?
7 in binary is 111. In hexadecimal it's 7.
What is 7 as a Roman numeral?
7 in Roman numerals is VII.
What's the digit sum of 7?
Adding the digits of 7: 7 = 7.