Q: What are the prime factors of the number 21,205,144?

 A: 2, 37, 71, 1009

Why are those the prime factors of the number 21,205,144?

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 21,205,144

21,205,144
Factor Arrows
210,602,572
Factor Arrows
25,301,286
Factor Arrows
22,650,643
Factor Arrows
3771,639
Factor Arrows
711,009

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, 37, 71, 1009

We can check our work by multiplying all of the prime factors together: 2 x 2 x 2 x 37 x 71 x 1,009 = 21,205,144

This can also be written as 23 x 371 x 711 x 1,0091 = 21,205,144

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


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