Factors of 45
The factors of 45 are the numbers that divide it exactly. Finding factors is the first step in simplifying fractions and factoring expressions.
A composite carrying 6 factors — factors always arrive in mirrored pairs, so the count comes out even. The largest prime factor is 5: 45 = 5 × 9. Every factor together sums to 78 — the proper divisors (all factors but 45 itself) add to 33, which is less than 45 itself, a deficient number. Shared factors between two numbers are what the GCF calculator hunts — the pairing column above feeds that search directly.
| Factor | Pairing |
|---|---|
| 1 | 1 × 45 = 45 |
| 3 | 3 × 15 = 45 |
| 5 | 5 × 9 = 45 |
| 9 | 9 × 5 = 45 |
| 15 | 15 × 3 = 45 |
| 45 | 45 × 1 = 45 |
Frequently asked questions
What are the factors of 45?
The factors of 45 are 1, 3, 5, 9, 15, 45 — that is 6 factors in total.
How do you find factors of 45?
Test each number from 1 up to 45: if it divides 45 with no remainder, it is a factor. Pair test — every factor pairs with a cofactor, like 1 × 3 = 45.
Why do factors matter for simplifying fractions?
Simplification divides both top and bottom by their greatest common factor — so a shared factor between two numbers, like you can find in the tables above, makes the fraction smaller and cleaner.