Q: What are the prime factors of the number 664,640?

 A: 2, 5, 31, 67

Why are those the prime factors of the number 664,640?

Prime factors are the prime numbers that can be multipled together to equal the original number. You find the factors by dividing by prime numbers. It is best shown by creating a Factor Tree.

Factor Tree for the number 664,640

664,640
Factor Arrows
2332,320
Factor Arrows
2166,160
Factor Arrows
283,080
Factor Arrows
241,540
Factor Arrows
220,770
Factor Arrows
210,385
Factor Arrows
52,077
Factor Arrows
3167

The numbers in bold above are the prime factors. If there are multiples, you only count them one time. This leads us to our prime factors of:

2, 5, 31, 67

We can check our work by multiplying all of the prime factors together: 2 x 2 x 2 x 2 x 2 x 2 x 5 x 31 x 67 = 664,640

This can also be written as 26 x 51 x 311 x 671 = 664,640

If you would like to know more, or need additional explanation, please review our prime factorization explanation.


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