Q: What are the prime factors of the number 644,405,440?

 A: 2, 5, 7, 287681

Why are those the prime factors of the number 644,405,440?

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 644,405,440

644,405,440
Factor Arrows
2322,202,720
Factor Arrows
2161,101,360
Factor Arrows
280,550,680
Factor Arrows
240,275,340
Factor Arrows
220,137,670
Factor Arrows
210,068,835
Factor Arrows
52,013,767
Factor Arrows
7287,681

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, 7, 287681

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 7 x 287,681 = 644,405,440

This can also be written as 26 x 51 x 71 x 287,6811 = 644,405,440

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


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