GCF and LCM of 45
Every pair this site works through that contains 45. 25 of them share a factor with it; 0 share nothing, which is its own kind of answer.
Shares a factor with 45
What 45 is made of
Every common factor 45 can share with anything comes from this list, which is why the pairs below look the way they do. 45 = 3² × 5, and that factorisation is unique — the fundamental theorem of arithmetic guarantees no other set of primes multiplies to it.
- Divisors (6)
- 1, 3, 5, 9, 15, 45
- As factor pairs
- 1×45, 3×15, 5×9
- Prime factorisation
- 3² × 5
- Divisors excluding itself add to
- 33 — deficient
Divisors come in pairs that multiply to 45, which is why there is an even number of them unless the number is a perfect square. The greatest common factor of 45 and any other number is the largest entry two lists like this one share.