Why is the prime factorization of 161,235,120 written as 24 x 31 x 51 x 4631 x 1,4511?
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 161,235,120
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 161,235,120 by 2
161,235,120 ÷ 2 = 80,617,560 - No remainder! 2 is one of the factors!
80,617,560 ÷ 2 = 40,308,780 - No remainder! 2 is one of the factors!
40,308,780 ÷ 2 = 20,154,390 - No remainder! 2 is one of the factors!
20,154,390 ÷ 2 = 10,077,195 - No remainder! 2 is one of the factors!
10,077,195 ÷ 2 = 5,038,597.5 - There is a remainder. We can't divide by 2 evenly anymore. Let's try the next prime number
10,077,195 ÷ 3 = 3,359,065 - No remainder! 3 is one of the factors!
3,359,065 ÷ 3 = 1,119,688.3333 - There is a remainder. We can't divide by 3 evenly anymore. Let's try the next prime number
3,359,065 ÷ 5 = 671,813 - No remainder! 5 is one of the factors!
671,813 ÷ 5 = 134,362.6 - There is a remainder. We can't divide by 5 evenly anymore. Let's try the next prime number
671,813 ÷ 7 = 95,973.2857 - This has a remainder. 7 is not a factor.
671,813 ÷ 11 = 61,073.9091 - This has a remainder. 11 is not a factor.
671,813 ÷ 13 = 51,677.9231 - This has a remainder. 13 is not a factor.
...
Keep trying increasingly larger numbers until you find one that divides evenly.
...
671,813 ÷ 463 = 1,451 - No remainder! 463 is one of the factors!
1,451 ÷ 463 = 3.1339 - There is a remainder. We can't divide by 463 evenly anymore. Let's try the next prime number
1,451 ÷ 467 = 3.1071 - This has a remainder. 467 is not a factor.
1,451 ÷ 479 = 3.0292 - This has a remainder. 479 is not a factor.
1,451 ÷ 487 = 2.9795 - This has a remainder. 487 is not a factor.
...
Keep trying increasingly larger numbers until you find one that divides evenly.
...
1,451 ÷ 1,451 = 1 - No remainder! 1,451 is one of the factors!
The orange divisor(s) above are the prime factors of the number 161,235,120. If we put all of it together we have the factors 2 x 2 x 2 x 2 x 3 x 5 x 463 x 1,451 = 161,235,120. It can also be written in exponential form as 24 x 31 x 51 x 4631 x 1,4511.
Factor Tree
Another way to do prime factorization is to use a factor tree. Below is a factor tree for the number 161,235,120.
| 161,235,120 | | | | | | | |
| ![Factor Arrows](/assets/img/factor-arrows.png) | | | | | | | |
2 | | 80,617,560 | | | | | | |
| | ![Factor Arrows](/assets/img/factor-arrows.png) | | | | | | |
| 2 | | 40,308,780 | | | | | |
| | | ![Factor Arrows](/assets/img/factor-arrows.png) | | | | | |
| | 2 | | 20,154,390 | | | | |
| | | | ![Factor Arrows](/assets/img/factor-arrows.png) | | | | |
| | | 2 | | 10,077,195 | | | |
| | | | | ![Factor Arrows](/assets/img/factor-arrows.png) | | | |
| | | | 3 | | 3,359,065 | | |
| | | | | | ![Factor Arrows](/assets/img/factor-arrows.png) | | |
| | | | | 5 | | 671,813 | |
| | | | | | | ![Factor Arrows](/assets/img/factor-arrows.png) | |
| | | | | | 463 | | 1,451 |
More Prime Factorization Examples
161,235,118 | 161,235,119 | 161,235,121 | 161,235,122 |
21 x 111 x 2571 x 28,5171 | 161,235,1191 | 191 x 2511 x 33,8091 | 21 x 371 x 431 x 50,6711 |
Try the
factor calculator