Primes / Is 71 prime?

Is 71 a Prime Number?

Yes

71 is prime: for 71, testing every prime up to √71 ≈ 8.4 (namely 2, 3, 5, 7) finds no divisor. 71 sits between primes 67 and 73, 4 below and 2 above. 71 shares no factor with 2-12; 71's divisors start beyond that range. 71 is odd, digit sum 8 for 71, digital root 8 for 71. 71 has 5 primes within 10 of 71.