Q: What are the prime factors of the number 221,440?

 A: 2, 5, 173

Why are those the prime factors of the number 221,440?

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 221,440

221,440
Factor Arrows
2110,720
Factor Arrows
255,360
Factor Arrows
227,680
Factor Arrows
213,840
Factor Arrows
26,920
Factor Arrows
23,460
Factor Arrows
21,730
Factor Arrows
2865
Factor Arrows
5173

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, 5, 173

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 2 x 2 x 5 x 173 = 221,440

This can also be written as 28 x 51 x 1731 = 221,440

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


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