Step 1 of 4 · What's a factor pair?
A factor pair of N is any two numbers that multiply to N. Pairs always come in twos — except when N is a perfect square.
For N = 12, the factor pairs are 1×12, 2×6, 3×4.
Factors of 12: 1, 2, 3, 4, 6, 12 — that's 6 factors.
Trick: only test divisors up to √N. Each hit gives you BOTH factors of the pair for free.
Step 2 of 4 · Find pairs of 12
12
Test 1, 2, 3, ... Stop at √12 ≈ 3.5.
factor pairs of 121×12 · 2×6 · 3×4