Q: What is the prime factorization of the number 28,127,833?

Why is the prime factorization of 28,127,833 written as 127¹ x 241¹ x 919¹?

What is prime factorization?

Prime factorization or prime factor decomposition is the process of finding which prime numbers can be multiplied together to make the original number.

Finding the prime factors of 28,127,833

To find the prime factors, you start by dividing the number by the first prime number, which is 2. If there is not a remainder, meaning you can divide evenly, then 2 is a factor of the number. Continue dividing by 2 until you cannot divide evenly anymore. Write down how many 2's you were able to divide by evenly. Now try dividing by the next prime factor, which is 3. The goal is to get to a quotient of 1.

Here are the first several prime factors: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29...

Let's start by dividing 28,127,833 by 2

28,127,833 ÷ 2 = 14,063,916.5 - This has a remainder. Let's try another prime number.
28,127,833 ÷ 3 = 9,375,944.3333 - This has a remainder. Let's try another prime number.
28,127,833 ÷ 5 = 5,625,566.6 - This has a remainder. Let's try another prime number.
...
Keep trying increasingly larger numbers until you find one that divides evenly.
...
28,127,833 ÷ 127 = 221,479 - No remainder! 127 is one of the factors!
221,479 ÷ 127 = 1,743.9291 - There is a remainder. We can't divide by 127 evenly anymore. Let's try the next prime number
221,479 ÷ 131 = 1,690.6794 - This has a remainder. 131 is not a factor.
221,479 ÷ 137 = 1,616.635 - This has a remainder. 137 is not a factor.
221,479 ÷ 139 = 1,593.3741 - This has a remainder. 139 is not a factor.
...
Keep trying increasingly larger numbers until you find one that divides evenly.
...
221,479 ÷ 241 = 919 - No remainder! 241 is one of the factors!
919 ÷ 241 = 3.8133 - There is a remainder. We can't divide by 241 evenly anymore. Let's try the next prime number
919 ÷ 251 = 3.6614 - This has a remainder. 251 is not a factor.
919 ÷ 257 = 3.5759 - This has a remainder. 257 is not a factor.
919 ÷ 263 = 3.4943 - This has a remainder. 263 is not a factor.
...
Keep trying increasingly larger numbers until you find one that divides evenly.
...
919 ÷ 919 = 1 - No remainder! 919 is one of the factors!

The orange divisor(s) above are the prime factors of the number 28,127,833. If we put all of it together we have the factors 127 x 241 x 919 = 28,127,833. It can also be written in exponential form as 127¹ x 241¹ x 919¹.

Factor Tree

Another way to do prime factorization is to use a factor tree. Below is a factor tree for the number 28,127,833.

	28,127,833
127		221,479
	241		919

More Prime Factorization Examples

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