Q: What are the prime factors of the number 642,640?

 A: 2, 5, 29, 277

Why are those the prime factors of the number 642,640?

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 642,640

642,640
Factor Arrows
2321,320
Factor Arrows
2160,660
Factor Arrows
280,330
Factor Arrows
240,165
Factor Arrows
58,033
Factor Arrows
29277

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, 29, 277

We can check our work by multiplying all of the prime factors together: 2 x 2 x 2 x 2 x 5 x 29 x 277 = 642,640

This can also be written as 24 x 51 x 291 x 2771 = 642,640

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


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