Q: What are the prime factors of the number 1,991,871?

 A: 3, 7, 1171

Why are those the prime factors of the number 1,991,871?

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 1,991,871

1,991,871
Factor Arrows
3663,957
Factor Arrows
3221,319
Factor Arrows
373,773
Factor Arrows
324,591
Factor Arrows
38,197
Factor Arrows
71,171

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, 7, 1171

We can check our work by multiplying all of the prime factors together: 3 x 3 x 3 x 3 x 3 x 7 x 1,171 = 1,991,871

This can also be written as 35 x 71 x 1,1711 = 1,991,871

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


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