Q: What are the prime factors of the number 21,811,240?

 A: 2, 5, 11, 19, 2609

Why are those the prime factors of the number 21,811,240?

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 21,811,240

21,811,240
Factor Arrows
210,905,620
Factor Arrows
25,452,810
Factor Arrows
22,726,405
Factor Arrows
5545,281
Factor Arrows
1149,571
Factor Arrows
192,609

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, 11, 19, 2609

We can check our work by multiplying all of the prime factors together: 2 x 2 x 2 x 5 x 11 x 19 x 2,609 = 21,811,240

This can also be written as 23 x 51 x 111 x 191 x 2,6091 = 21,811,240

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


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