Prime Factorization Calculator
Break down any composite number into its prime factors. View the results instantly in both expanded multiplication and condensed exponential forms.
Last updated: March 3, 2026
xⁿ ExponentsWhat are Primes?
Primes are the "atoms" of mathematics. You can build every other single number by multiplying them together!
Building the Factor Tree
You can manually find the prime factorization of a number by drawing a factor tree. It involves successive division until you are left with nothing but prime numbers at the "leaves" of the tree.
Step 1: Divide by 2
Always start with the smallest prime number, which is 2. If the number is even, divide it by 2. Continue dividing the resulting quotients by 2 until you get an odd number.
For example, with the number 84:
84 ÷ 2 = 42
42 ÷ 2 = 21
Step 2: Ascend through Primes
Once the number is odd, you can no longer divide by 2. Move to the next prime, which is 3. Does 3 go in evenly? If yes, keep dividing by 3. Once 3 no longer works, move to 5, then 7, then 11, and so forth.
Continuing from 21:
21 ÷ 3 = 7
The number 7 is prime, so we stop! Our factors are 2, 2, 3, and 7.
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