Primes / Is 509 prime?

Is 509 a Prime Number?

Yes

509 is prime: for 509, testing every prime up to √509 ≈ 22.6 (namely 2, 3, 5, 7, 11, 13, 17, 19) finds no divisor. 509 sits between primes 503 and 521, 6 below and 12 above. 509 shares no factor with 2-12; 509's divisors start beyond that range. 509 is odd, digit sum 14 for 509, digital root 5 for 509. 509 has 3 primes within 10 of 509.