Q: What are the prime factors of the number 21,120,008?

 A: 2, 7, 13, 67, 433

Why are those the prime factors of the number 21,120,008?

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 21,120,008

21,120,008
Factor Arrows
210,560,004
Factor Arrows
25,280,002
Factor Arrows
22,640,001
Factor Arrows
7377,143
Factor Arrows
1329,011
Factor Arrows
67433

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, 7, 13, 67, 433

We can check our work by multiplying all of the prime factors together: 2 x 2 x 2 x 7 x 13 x 67 x 433 = 21,120,008

This can also be written as 23 x 71 x 131 x 671 x 4331 = 21,120,008

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


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