Q: What are the prime factors of the number 687,840?

 A: 2, 3, 5, 1433

Why are those the prime factors of the number 687,840?

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 687,840

687,840
Factor Arrows
2343,920
Factor Arrows
2171,960
Factor Arrows
285,980
Factor Arrows
242,990
Factor Arrows
221,495
Factor Arrows
37,165
Factor Arrows
51,433

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, 1433

We can check our work by multiplying all of the prime factors together: 2 x 2 x 2 x 2 x 2 x 3 x 5 x 1,433 = 687,840

This can also be written as 25 x 31 x 51 x 1,4331 = 687,840

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


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