Primes / Is 313 prime?

Is 313 a Prime Number?

Yes

313 is prime: for 313, testing every prime up to √313 ≈ 17.7 (namely 2, 3, 5, 7, 11, 13, 17) finds no divisor. 313 sits between primes 311 and 317, 2 below and 4 above. 313 shares no factor with 2-12; 313's divisors start beyond that range. 313 is odd, digit sum 7 for 313, digital root 7 for 313. 313 has 4 primes within 10 of 313.