Primes / Is 331 prime?

Is 331 a Prime Number?

Yes

331 is prime: for 331, testing every prime up to √331 ≈ 18.2 (namely 2, 3, 5, 7, 11, 13, 17) finds no divisor. 331 sits between primes 317 and 337, 14 below and 6 above. 331 shares no factor with 2-12; 331's divisors start beyond that range. 331 is odd, digit sum 7 for 331, digital root 7 for 331. 331 has 2 primes within 10 of 331.