Factors of 20

The factors of 20 are all the positive and negative integers which give you the result as number 20 when you multiply two numbers together. The factor pairs of 20 are the whole numbers that can be either positive or negative but cannot be a fraction or a decimal number. To find all factors of 20, you can use the prime factorization of 20 method.


In the prime factorization method, you need to first consider the two numbers 1 and 20 as the factors and then continue to find the other pair of multiples of 20 that would give you the results as an original number. For understanding this method in a better way, read the article below for finding the factors of 20 in pairs. Also, you will find the method to find the prime factors of 20 by using the division method.


The factor pairs of 20 are the combinations of two factors which when multiplied together equals to the number 20. Given below are all the positive factor pairs of 20 and all the negative factor pairs of 20.

Factor Pairs of 20

1 x 20 = 20

2 x 10 = 20

4 x 5 = 20

5 x 4 = 20

10 x 2 = 20

20 x 1 = 20


The factors of 20 consists of negative pairs as well because multiplying two negative numbers gives you a positive integer. Hence, you can simply put a minus sign in front of all the numbers of the factor pairs of 20.


-1 x -20 = 20

-2 x -10 = 20

-4 x -5 = 20

-5 x -4 = 20

-10 x -2 = 20

-20 x -1 = 20


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How to Find the Factors of 20?

To find all factors of 20, follow the following steps:

  1. The first step is writing down the number 20.

  1. Then, find the two numbers such that they give the result as 20 when you multiply them together. For example, 2 and 10. Multiplying them gives you 2 × 10 = 20.

  1. You would know that 2 is a prime number and has only two factors, that is, 1 and the number itself. Hence, you cannot factorize 2 further since 2 x 1 = 2.

  1. However, 10 is a composite number and not a prime number. Hence, you can factorize it further as 10 = 2 × 5 × 1.

  1. Therefore, the factorization of 20 can be written as:

 20 = 2 × 2 × 5 × 1

  1. Finally, you need to write down all the unique numbers that you can obtain from the number 20. Doing so you get,

20 = 2 × 2 × 5 × 1

Hence, all the factors of 20 are 1, 2, 4, 5, 10, and 20.


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Prime Factorization of 20

Since the number 20 is a composite number, it consists of prime factors. Now, let us find the prime factors of 20 using the prime factorization method.

  1. The first step is dividing the number 20 with the smallest prime factor, which is 2 in this case.

Doing so, you get, 20 ÷ 2 = 10

  1. Now, again, divide the number 10 by 2 since 10 is a composite number and can be further divided.

Diving 10 by 2, you get, 10÷ 2 = 5

  1. Now, if you divide 5 by 2 you would get a fractional number, and that cannot be a factor.

So, the next step is to proceed with the next prime numbers which is 5.

  1. Since 5 is also a prime number and cannot be divided further, you divide it by the number itself.

Dividing the number 5 by itself gives you 5 ÷ 5 = 1

Now, you have received 1 at the end of the division process and it is not possible to proceed further. 

Hence, the prime factors of 20 can be written as 2 × 2 × 5, or 22 × 5, 

where 2 and 5 are the prime factors of 20.


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FAQ (Frequently Asked Questions)

1. List all the factors of 20

All the factors of 20 include 1, 2, 4, 5, 10, and 20.

2. What is the prime factorization of 20?

The prime factorization of 20 gives you 2 × 2 × 5 which can also be written as 22 × 5. You can use the factor tree method to find the prime factors of 20.


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3. What are the common factors of 20 and the number 25?

The factors of 20 include the numbers 1, 2, 4, 5, and 20, and the factors of 25 include the numbers 1, 5, and 25.

Hence, the common factors of 20 and 25 are the numbers 1 and 5.