# Factors of 21 – With Easy Division and Prime Factorization

Contents

**Factors OF 21**

A factor of 21 is the result of multiplying a pair of factors to give the result of 21. Factors divide the numbers uniformly.

**The factors of 21 are 1, 3, 7, and 21. **

When these numbers are multiplied together, they give the number 21. We can use the factorization method to find the factors of the number 21.

**How to Find the Factors of 21?**

To find the factors of 21, follow the steps below.

Start by writing the number 21

Find the two numbers, say 3 and 7, which result in 21 when multiplied, such that 3 × 7 = 21.

It is known that 3 and 7 are prime numbers with just two factors, the number itself and one.

The factors of 3 = 3 × 1

Factors of 7 = 7 x 1

Therefore, we can’t further factorize them.

As a consequence, the factorization of 21 can be expressed as 21 = 3 × 7 × 1

Finally, list all the unique numbers obtained through the above process.

Factors of 21:

1, 3, 7, and 21

**Pair Factors of 21**

If you want to know the factors of 21, multiply the two numbers to get the original number. Both positive and negative integers can be written as pairs as follows:

Positive pairs | Negative pairs |

1 × 21 = 21; (1, 21) | (-1) × (-21) = 21; (-1, -21) |

3 × 7 = 21; (3, 7) | (-3) × (-7) = 21; (-3, -7) |

7 × 3 = 21; (7, 3) | (-7) × (-3) = 21; (-7, -3) |

21 × 1 = 21; (21, 1) | (-21) × (-1) = 21; (-21, -1) |

Consequently, (1, 21), (3, 7), (7, 3), and (21, 1) are the** positive pair factors **of 21.

In addition to (-1, -21), (-3, -7), (-7, -3), (-21, -1) are the **negative pair factors** of 21.

**Prime Factors of 21**

It is well known that 21 has prime factors, and it is a composite number. Let’s see what those factors are.

- To begin, divide 21 by the smallest prime number, i.e., 2.

21 ÷ 2 = 10.5

In other words, 2 cannot be a factor of 21 because factors should be whole numbers. Therefore, we will proceed to the following prime number, i.e., 3.

21 ÷ 3 = 7

Therefore, 3 is one of the prime factors of 21.

You can now divide 7 by the prime numbers.

7 ÷ 2 = 3.5

7 ÷ 3 = 2.333

7 ÷÷ 5 = 1.4

7 ÷ 7 = 1

- In the division process, we received number 1, which means we cannot move forward.

In other words, the** prime factors of 21** are** 3 and 7**, whereas 2 and 7 are prime numbers, respectively.

According to principle, we can factorize 21 as 3 × 7.

**Notables:**

Here are a few facts about 21:

- There are four factors in 21.
- The sum of all the factors of 21 is 32.
- When all factors of 21 are added together, the sum equals the square of 21 or 21 times 21.

Links Related to Factors | |

Composite Factors of 24= 1, 2, 3, 4, 6, 8, 12, and 24. | Factors of 36= 1, 2, 3, 4, 6, 9, 12, 18, and 36. |

Factors of 48= 1, 2, 3, 4, 6, 8, 12, 16, 24, and 48. | Composite Factors of 57= 1, 3, 29, and 57. |

Factors of 42= 1, 2, 3, 6, 7, 14, 21, and 42. | Factors of 60= 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30 and 60. |

Factors of 35= 1, 5, 7, and 35. | Factors of 72= 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36 and 72. |

Factors of 84= 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42 and 84. | Composite Factors of 22= 1, 2, 11, and 22. |

**FAQs**

**Can you tell me the multiples and factors of 21?**

Among the multiples of 21, there are 21, 42, 63, 84, 105, 126, 147, 168, 189, 210, etc.

21 has the factors 1, 3, 7, and 21.

**How many multiples of 21 are there?**

21, 42, 63, 84, 105, 126, 147, 168, 189, 210, … are all multiples of 21.

**Can you tell me the factors of 21 and 24?**

21 has the factors 1, 3, 7, and 21.

24 has the following factors: 1, 2, 3, 4, 6, 8, 12, and 24.

**Does 21 only have 2 factors?**

Other than 1 and 21, the number 21 has 2 more factors: 1, 3, 7, and 21.

**What are the three numbers that make 21?**

As an example, we have multiple sets of three numbers that add up to 21 as follows:

6, 7, 8 (6 + 7 + 8 = 21)

3, 8, 10 (3 + 8 + 10 = 21)**Get Factors of More Numbers Here**

Factors of 23= 1, 23

Factors of 24=1, 2, 3, 4, 6, 8, 12, and 24.

Factors of 27=1, 3, 9, and 27.

Factors of 28=1, 2, 4, 7, 14, and 28.

Factors of 30=1, 2, 3, 5, 6, 10, 15 and 30.