The number 11 only has two factors, which are 1 and 11. The number 11 is an example of a prime number, which is any number that only has two factors, 1 and itself.
A factor of a number is any number that is equal to or smaller than the number of interest that can be divided equally into the original number. For example, 9 can be divided by 3 to result in 3 with no remainder, which means that 3 is a factor of 9. Non-prime numbers have more than two factors. For example, nine has the factors of 1, 3 and 9, making it a non-prime number.