Prime Factorization Examples

What's the prime factorization of 45?

For starters, 45 is odd, so it's not divisible by 2. The next largest prime number is 3, which does divide into 45.

45 = 3 × 15
45 = 3 × 3 × 5

What's the prime factorization of 1320?

1320 = 66 × 20
= (6 × 11) × (2 × 10)
= (2 × 3 × 11) × (2 × 2 × 5)
= 2 × 2 × 2 × 3 × 5 × 11