Q: What are the prime factors of the number 399,990?

 A: 2, 3, 5, 67, 199

Why are those the prime factors of the number 399,990?

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 399,990

399,990
Factor Arrows
2199,995
Factor Arrows
366,665
Factor Arrows
513,333
Factor Arrows
67199

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, 67, 199

We can check our work by multiplying all of the prime factors together: 2 x 3 x 5 x 67 x 199 = 399,990

This can also be written as 21 x 31 x 51 x 671 x 1991 = 399,990

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


More Examples

Here are some more numbers to try:

Try the factor calculator

Explore more about the number 399,990:


Ask a Question