odd, prime, palindrome · 11th positive integer
The number 11
11 is an odd prime number. It's known as a repunit, a palindrome, and the first prime that is also a palindrome. It is the 11th positive integer.
Quick reference
| Prime factorization | 11 (prime) |
| Divisors | 1, 11 |
| Binary | 1011 |
| Hexadecimal | 0xB |
| Roman numeral | XI |
| Digit sum | 2 |
| Properties | odd, prime, palindrome |
Why 11 is notable
A repunit, a palindrome, and the first prime that is also a palindrome.
Frequently asked
Is 11 a prime number?
Yes. 11 is prime — its only divisors are 1 and itself.
What are the factors of 11?
The factors (divisors) of 11 are 1, 11.
What is 11 in binary?
11 in binary is 1011. In hexadecimal it's B.
What is 11 as a Roman numeral?
11 in Roman numerals is XI.
What's the digit sum of 11?
Adding the digits of 11: 1 + 1 = 2.