Factors of 21

Factors of 21 are all the numbers that are divisible into 21 without any remainders. These factors are whole numbers and can be both positive and negative. In this page, we will learn how to find out all the factors of 21, including prime factors of 21.

• Factors of 21 are : 1, 3, 7, 21
• Prime Factors of 21 : 21 = 3 × 7

Multiplication

1 x 21

3 x 7

Positive pair
factors of 21

(1, 21)

(3, 7)

Negative pair
factors of 21

(-1, -21)

(-3, -7)

Prime Factors of 21

To obtin the prime factors of 21, you need to find the factors of 21 and divide them out.

• 21 divided by 3 is 7
• 3 and 7 is a prime number
• You get the final breakdown of the 21 = 3 × 7

Alternately, we can organize all the prime factors of 21 using a tree diagram:

To list out all the prime factors : 21 = 3 × 7

How to Calculate the Factors of 21

Factors must be the whole numbers, which means fractions like 5.6 is not considered as a factor. We use the integers to divide 21, if there is no remainder, then the integers you use are the factors of 21. We can always dividing 21 by 1 to get started, then move to different integers.

21/1 = 21 (Factor = 1 and remainder = 0)

21/3 = 7 (Factor = 3 and remainder = 0)

Note:

If we divide 56 by numbers other than 1, 2, 4, 7, 8, 14, 28 and 56, there must be a remainder. Let us try 3,

Examples

1. Find the common factors of 23 and 56

The factors of 23 are: 1,23. (23 is a prime number)
The factors of 56 are 1, 2, 4, 7, 8, 14, 28 and 56

2. Find the common factors of 52 and 56

The factors of 52 are: 1, 2, 4, 13, 26, and 52.
The factors of 56 are 1, 2, 4, 7, 8, 14, 28 and 56

3. Find the common factors of 33 and 56

The factors of 33 are: 1, 3, 11 and 33.
The factors of 56 are 1, 2, 4, 7, 8, 14, 28 and 56

FAQ - Factor of 56

What are the multiples of 56?

1x56=52, 2x56=112, 3x56=168, 4x56=224, 5x56=280...

Is 56 prime or composite?

Composite number, because 56 can be divided evenly by 1 and 56, (2, 28), (4, 14), (7, 8) are also the pairs of factors of 56

How many prime factors are there in 56?

The prime factors of 56 = 2x2x2x7, which means there are 2 prime factors in 56, they are 2 and 7.

What is the perfect number?

The perfect number is a positive integar that equal to the sum of its proper divisors.( not include itself) For example, 6 is the smallest perfect number, the factors of 6 are: 1,2,3,6. 6=1+2+3

Do numbers end?

No, numbers are infinite and never end.