Q: What are the prime factors of the number 257,145?

 A: 3, 5, 7, 31, 79

Why are those the prime factors of the number 257,145?

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 257,145

257,145
Factor Arrows
385,715
Factor Arrows
517,143
Factor Arrows
72,449
Factor Arrows
3179

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, 5, 7, 31, 79

We can check our work by multiplying all of the prime factors together: 3 x 5 x 7 x 31 x 79 = 257,145

This can also be written as 31 x 51 x 71 x 311 x 791 = 257,145

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


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