Q: What are the prime factors of the number 640,872?

 A: 2, 3, 23, 43

Why are those the prime factors of the number 640,872?

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 640,872

640,872
Factor Arrows
2320,436
Factor Arrows
2160,218
Factor Arrows
280,109
Factor Arrows
326,703
Factor Arrows
38,901
Factor Arrows
32,967
Factor Arrows
3989
Factor Arrows
2343

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, 3, 23, 43

We can check our work by multiplying all of the prime factors together: 2 x 2 x 2 x 3 x 3 x 3 x 3 x 23 x 43 = 640,872

This can also be written as 23 x 34 x 231 x 431 = 640,872

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


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