Factors / Factors of 521

Factors of 521

1, 521

521 is prime: only factor pair is (1, 521), confirmed by trial division up to √521 ≈ 22.8 turning up nothing else. 521's full pair list is (1, 521), for 2 divisors in total. 521's divisors other than 521 itself sum to just 1, 520 below 521: the common deficient case. 521 is odd, digit sum 8 for 521; none of 2-12 divide 521 evenly. 521 has 2 divisors; 520 has 16 and 522 has 12, so 520 wins here. 521 divided by its largest divisor, 1, gives 521.