Primes / Is 19 prime?

Is 19 a Prime Number?

Yes

19 is prime: for 19, testing every prime up to √19 ≈ 4.4 (namely 2, 3) finds no divisor. 19 sits between primes 17 and 23, 2 below and 4 above. 19 shares no factor with 2-12; 19's divisors start beyond that range. 19 is odd, digit sum 10 for 19, digital root 1 for 19. 19 has 6 primes within 10 of 19.