Primes / Is 139 prime?

Is 139 a Prime Number?

Yes

139 is prime: for 139, testing every prime up to √139 ≈ 11.8 (namely 2, 3, 5, 7, 11) finds no divisor. 139 sits between primes 137 and 149, 2 below and 10 above. 139 shares no factor with 2-12; 139's divisors start beyond that range. 139 is odd, digit sum 13 for 139, digital root 4 for 139. 139 has 4 primes within 10 of 139.