Q: What are the prime factors of the number 420,240?

 A: 2, 3, 5, 17, 103

Why are those the prime factors of the number 420,240?

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 420,240

420,240
Factor Arrows
2210,120
Factor Arrows
2105,060
Factor Arrows
252,530
Factor Arrows
226,265
Factor Arrows
38,755
Factor Arrows
51,751
Factor Arrows
17103

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, 103

We can check our work by multiplying all of the prime factors together: 2 x 2 x 2 x 2 x 3 x 5 x 17 x 103 = 420,240

This can also be written as 24 x 31 x 51 x 171 x 1031 = 420,240

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


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