Q: What are the prime factors of the number 21,007,749?

 A: 3, 7, 19, 37, 1423

Why are those the prime factors of the number 21,007,749?

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 21,007,749

21,007,749
Factor Arrows
37,002,583
Factor Arrows
71,000,369
Factor Arrows
1952,651
Factor Arrows
371,423

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, 19, 37, 1423

We can check our work by multiplying all of the prime factors together: 3 x 7 x 19 x 37 x 1,423 = 21,007,749

This can also be written as 31 x 71 x 191 x 371 x 1,4231 = 21,007,749

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


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