Primes / Is 191 prime?

Is 191 a Prime Number?

Yes

191 is prime: for 191, testing every prime up to √191 ≈ 13.8 (namely 2, 3, 5, 7, 11, 13) finds no divisor. 191 sits between primes 181 and 193, 10 below and 2 above. 191 shares no factor with 2-12; 191's divisors start beyond that range. 191 is odd, digit sum 11 for 191, digital root 2 for 191. 191 has 5 primes within 10 of 191.