Prime Factorization of 15

Find the prime factorization of 15. Express 15 as a product of prime numbers.

Prime factorization of
Answer: 15 = 3 × 5
Step-by-Step Solution
Step 1 Understand Prime Factorization

To find the prime factorization of 15, we need to express it as a product of prime numbers.


We do this by repeatedly dividing by the smallest prime that divides evenly, starting with 2.

A prime number is only divisible by 1 and itself (2, 3, 5, 7, 11, 13, ...).

Step 2 Check Divisibility by 2

15 is an odd number, so it is not divisible by 2.

We move on to check the next prime number: 3.

Step 3 Divide by 3

3 is a prime number that divides our current value. We can divide by 3 once:


15 ÷ 3 = 5

After dividing by 3, we have 5 remaining.

Step 4 Final Prime Factor

We are left with 5, which is greater than 1.

5 cannot be divided by any prime smaller than its square root.

Therefore, 5 is itself a prime number and is our final factor.

Step 5 Write the Prime Factorization

Now we combine all the prime factors we found:


Expanded form: 15 = 3 × 5


Exponential form: 15 = 3 × 5


We can verify: 3 × 5 = 15 ✓