What is the prime factorization of 45?

The prime factorization of 45 is 3 x 3 x 5 or 3^2 x 5 in exponential form.

The prime factors of any number are found by repeated division by primes until a quotient of 1 is obtained. We only take note of those divisors which divide into the number evently.

45 divided by 3 = 15

15 divided by 3 = 5

5 divided by 5 = 1

So, all the divisors which evenly divided into the number must be assembled and become the prime factors - in this case, the prime factors of 45 are 3, 3 and 5.
3 x 3 x 5
The prime factorisation of 45 is 3 x 3 x 5.
3x3x5
3 x 3 x 5 = 45