Q: What are the prime factors of the number 21,009,072?

 A: 2, 3, 7, 31, 2017

Why are those the prime factors of the number 21,009,072?

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 21,009,072

21,009,072
Factor Arrows
210,504,536
Factor Arrows
25,252,268
Factor Arrows
22,626,134
Factor Arrows
21,313,067
Factor Arrows
3437,689
Factor Arrows
762,527
Factor Arrows
312,017

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, 7, 31, 2017

We can check our work by multiplying all of the prime factors together: 2 x 2 x 2 x 2 x 3 x 7 x 31 x 2,017 = 21,009,072

This can also be written as 24 x 31 x 71 x 311 x 2,0171 = 21,009,072

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


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