Factors of 21 in pair are (1, 21) , (3, 7)

- Find all the numbers that would divide 21 without leaving any remainder. Starting with the number 1 upto 10 (half of 21). The number 1 and the number itself are always factors of the given number.
- Pair the factors so that their product is 21, and read off the answer!

Factor Pair | Pair Factorization |
---|---|

1 and 21 | 1 x 21 = 21 |

3 and 7 | 3 x 7 = 21 |

Since the product of two negative numbers gives a positive number, the product of the negative values of both the numbers in a pair factor will also give 21. They are called negative pair factors.

Hence, the negative pairs of 21 would be ( -1 , -21 ) .

Factor pair in mathematics is defined as all factors of a given number which when written in pair and multiplied gives the original number. Every natural number is a product of atleast one factor pair. Eg- Factors of 21 are 1 , 3 , 7 , 21. So, factors of 21 in pair are (1,21), (3,7).

In mathematics a factor is a number which divides into another without leaving any remainder. Or we can say, any two numbers that multiply to give a product are both factors of that product. It can be both positive or negative.

- Every factor of a number is an exact divisor of that number, example 1, 3, 7, 21 are exact divisors of 21.
- Every number other than 1 has at least two factors, namely the number itself and 1.
- Each number is a factor of itself. Eg. 21 is a factor of itself.
- 1 is a factor of every number. Eg. 1 is a factor of 21.

**Step 1.**Find all the numbers that would divide 21 without leaving any remainder. Starting with the number 1 upto 10 (half of 21). The number 1 and the number itself are always factors of the given number.21 ÷ 1 : Remainder = 021 ÷ 3 : Remainder = 021 ÷ 7 : Remainder = 021 ÷ 21 : Remainder = 0

Hence, Factors of
*21* are **1, 3, 7, and 21**

**Is 21 a composite number?**Yes 21 is a composite number.

**Is 21 a perfect square?**No 21 is not a perfect square.

**Write all odd factors of 21?**The factors of 21 are 1, 3, 7, 21.

Odd factors of 21 are 1 , 3 , 7 , 21.**What is the mean of all prime factors of 21?**Factors of 21 are 1 , 3 , 7 , 21. Prime factors of 21 are 3 , 7. Therefore mean of prime factors of 21 is (3 + 7) / 2 = 5.00.

**What do you mean by proper divisors?**A number x is said to be the proper divisor of y if it divides y completely, given that x is smaller than y.

Factors of 21 are 1, 3, 7, 21. So, factors of 21 in pair are (1,21), (3,7).

Factors of 21 are 1, 3, 7, 21. So, factors of 21 in pair are (1,21), (3,7).

Factors of 21 are 1, 3, 7, 21. Hence, the factors of 21 in pair are (1,21), (3,7).

Factors of 21 are 1, 3, 7, 21.

Factors of 21 in pair are (1,21), (3,7).

Prime factorization of 21 is 3 x 7. Factors of 21 in pair can be written as (1,21), (3,7).

Smallest prime factor of 21 is 3.

Largest prime factor of 21 is 7.

Negative factors of 21 are -1, -3, -7, -21.