# Q: What is the prime factorization of the number 845,123?

A:
• The prime factors are: 419 x 2,017
• or also written as { 419, 2,017 }
• Written in exponential form: 4191 x 2,0171

## Why is the prime factorization of 845,123 written as 4191 x 2,0171?

### 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 845,123

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.

#### If it doesn't make sense yet, let's try it...

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

Let's start by dividing 845,123 by 2

845,123 ÷ 2 = 422,561.5 - This has a remainder. Let's try another prime number.
845,123 ÷ 3 = 281,707.6667 - This has a remainder. Let's try another prime number.
845,123 ÷ 5 = 169,024.6 - This has a remainder. Let's try another prime number.
...
Keep trying increasingly larger numbers until you find one that divides evenly.
...
845,123 ÷ 419 = 2,017 - No remainder! 419 is one of the factors!
2,017 ÷ 419 = 4.8138 - There is a remainder. We can't divide by 419 evenly anymore. Let's try the next prime number
2,017 ÷ 421 = 4.791 - This has a remainder. 421 is not a factor.
2,017 ÷ 431 = 4.6798 - This has a remainder. 431 is not a factor.
2,017 ÷ 433 = 4.6582 - This has a remainder. 433 is not a factor.
...
Keep trying increasingly larger numbers until you find one that divides evenly.
...
2,017 ÷ 2,017 = 1 - No remainder! 2,017 is one of the factors!

The orange divisor(s) above are the prime factors of the number 845,123. If we put all of it together we have the factors 419 x 2,017 = 845,123. It can also be written in exponential form as 4191 x 2,0171.

### Factor Tree

Another way to do prime factorization is to use a factor tree. Below is a factor tree for the number 845,123.

 845,123 419 2,017

### More Prime Factorization Examples

 845,121 845,122 845,124 845,125 31 x 171 x 731 x 2271 21 x 311 x 431 x 3171 22 x 31 x 71 x 10,0611 53 x 6,7611

Try the factor calculator

### Explore more about the number 845,123:

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