Factors / Factors of 45

Factors of 45

1, 3, 5, 9, 15, 45

45 breaks into 3 pairs, tested up to √45 ≈ 6.7; each pair multiplies back to 45 exactly. 45's full pair list is (1, 45), (3, 15), (5, 9), for 6 divisors in total. 45's divisors other than 45 itself sum to just 33, 12 below 45: the common deficient case. 45 is odd, digit sum 9 for 45; small divisors of 45 include 3, 5, 9. 45 has 6 divisors; 44 has 6 and 46 has 4, so 44 wins here. 45 divided by its largest divisor, 15, gives 3.