Q: What are the prime factors of the number 121,203,540?

 A: 2, 3, 5, 17, 163

Why are those the prime factors of the number 121,203,540?

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 121,203,540

121,203,540
Factor Arrows
260,601,770
Factor Arrows
230,300,885
Factor Arrows
310,100,295
Factor Arrows
33,366,765
Factor Arrows
31,122,255
Factor Arrows
3374,085
Factor Arrows
3124,695
Factor Arrows
341,565
Factor Arrows
313,855
Factor Arrows
52,771
Factor Arrows
17163

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, 17, 163

We can check our work by multiplying all of the prime factors together: 2 x 2 x 3 x 3 x 3 x 3 x 3 x 3 x 3 x 5 x 17 x 163 = 121,203,540

This can also be written as 22 x 37 x 51 x 171 x 1631 = 121,203,540

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


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