Q: What are the prime factors of the number 221,760?

 A: 2, 3, 5, 7, 11

Why are those the prime factors of the number 221,760?

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 221,760

221,760
Factor Arrows
2110,880
Factor Arrows
255,440
Factor Arrows
227,720
Factor Arrows
213,860
Factor Arrows
26,930
Factor Arrows
23,465
Factor Arrows
31,155
Factor Arrows
3385
Factor Arrows
577
Factor Arrows
711

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, 11

We can check our work by multiplying all of the prime factors together: 2 x 2 x 2 x 2 x 2 x 2 x 3 x 3 x 5 x 7 x 11 = 221,760

This can also be written as 26 x 32 x 51 x 71 x 111 = 221,760

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


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