Q: What are the prime factors of the number 21,058,191?

 A: 3, 7, 11, 1447

Why are those the prime factors of the number 21,058,191?

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 21,058,191

21,058,191
Factor Arrows
37,019,397
Factor Arrows
32,339,799
Factor Arrows
3779,933
Factor Arrows
7111,419
Factor Arrows
715,917
Factor Arrows
111,447

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, 7, 11, 1447

We can check our work by multiplying all of the prime factors together: 3 x 3 x 3 x 7 x 7 x 11 x 1,447 = 21,058,191

This can also be written as 33 x 72 x 111 x 1,4471 = 21,058,191

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


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