1. It is a prime number, that is, it is divisble only by 1 and itself.

2. It is the smallest two-digit prime number.

3. It is a twin prime as it is only two units away from the neighboring primes 7 and 13.

4. It is a sexy prime as it is only 6 units away from 5 and 17.

5. It is the smallest repunit prime; that is, it contains only 1 and is a prime.

6. It is the smallest two-digit numeric palindrome in decimal; that is, it is read the same forward and backward.

7. The sum of the digits of 11 is 2, which is also prime. Additionally, 2 is the only even prime.

8. Its digital root (repetitive sum of digits) is 2, which is also prime.

9.  It is a part of the prime quadruplet (11, 13, 17, 19), which consists of four prime numbers that are consecutive odd integers.

10. Multiplication of 11 by any single digit number, n, yields repdigit nn.

11. It is the first strong prime, that is, greater than the average of the neighboring primes (11>(7+13)/2).