Factors / Factors of 18

Factors of 18

1, 2, 3, 6, 9, 18

18 breaks into 3 pairs, tested up to √18 ≈ 4.2; each pair multiplies back to 18 exactly. 18's full pair list is (1, 18), (2, 9), (3, 6), for 6 divisors in total. 18's divisors other than 18 itself sum to 21, 3 above 18: abundant. 18 is even, digit sum 9 for 18; small divisors of 18 include 2, 3, 6, 9. 18 has 6 divisors; 17 has 2 and 19 has 2, so 18 wins here. 18 divided by its largest divisor, 9, gives 2.