Q: What are the prime factors of the number 918,540?

 A: 2, 3, 5, 7

Why are those the prime factors of the number 918,540?

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 918,540

918,540
Factor Arrows
2459,270
Factor Arrows
2229,635
Factor Arrows
376,545
Factor Arrows
325,515
Factor Arrows
38,505
Factor Arrows
32,835
Factor Arrows
3945
Factor Arrows
3315
Factor Arrows
3105
Factor Arrows
335
Factor Arrows
57

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, 7

We can check our work by multiplying all of the prime factors together: 2 x 2 x 3 x 3 x 3 x 3 x 3 x 3 x 3 x 3 x 5 x 7 = 918,540

This can also be written as 22 x 38 x 51 x 71 = 918,540

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


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