Q: What are the prime factors of the number 31,218,705?

 A: 3, 5, 7, 23, 31, 139

Why are those the prime factors of the number 31,218,705?

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 31,218,705

31,218,705
Factor Arrows
310,406,235
Factor Arrows
33,468,745
Factor Arrows
5693,749
Factor Arrows
799,107
Factor Arrows
234,309
Factor Arrows
31139

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:

3, 5, 7, 23, 31, 139

We can check our work by multiplying all of the prime factors together: 3 x 3 x 5 x 7 x 23 x 31 x 139 = 31,218,705

This can also be written as 32 x 51 x 71 x 231 x 311 x 1391 = 31,218,705

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


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