Q: What are the prime factors of the number 21,128,280?

 A: 2, 3, 5, 17, 10357

Why are those the prime factors of the number 21,128,280?

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 21,128,280

21,128,280
Factor Arrows
210,564,140
Factor Arrows
25,282,070
Factor Arrows
22,641,035
Factor Arrows
3880,345
Factor Arrows
5176,069
Factor Arrows
1710,357

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, 10357

We can check our work by multiplying all of the prime factors together: 2 x 2 x 2 x 3 x 5 x 17 x 10,357 = 21,128,280

This can also be written as 23 x 31 x 51 x 171 x 10,3571 = 21,128,280

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


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