Q: What are the prime factors of the number 21,646,440?

 A: 2, 3, 5, 17, 131

Why are those the prime factors of the number 21,646,440?

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 21,646,440

21,646,440
Factor Arrows
210,823,220
Factor Arrows
25,411,610
Factor Arrows
22,705,805
Factor Arrows
3901,935
Factor Arrows
3300,645
Factor Arrows
3100,215
Factor Arrows
333,405
Factor Arrows
311,135
Factor Arrows
52,227
Factor Arrows
17131

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, 5, 17, 131

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 3 x 5 x 17 x 131 = 21,646,440

This can also be written as 23 x 35 x 51 x 171 x 1311 = 21,646,440

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


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