Primes / Is 281 prime?

Is 281 a Prime Number?

Yes

281 is prime: for 281, testing every prime up to √281 ≈ 16.8 (namely 2, 3, 5, 7, 11, 13) finds no divisor. 281 sits between primes 277 and 283, 4 below and 2 above. 281 shares no factor with 2-12; 281's divisors start beyond that range. 281 is odd, digit sum 11 for 281, digital root 2 for 281. 281 has 4 primes within 10 of 281.