311

311 is a prime number.

311 and 313 form a twin prime pair.

311 is the 11th three-digit prime for which the sum of the squares of its digits is also a prime: 3² + 1² + 1² = 11, a prime.

311 is the smallest number expressible as the sum of consecutive primes in four ways: 311 = 101 + 103 + 107 = 53 + 59 + 61 + 67 + 71 = 31 + 37 + 41 + 43 + 47 + 53 + 59 = 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43 + 47.

311 is a rock/reggae band.

Source: Prime Curios!