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Greatest Common Factor of 21 and 35

Make use of GCF Calculator to quickly find the Greatest Common Factor of numbers 21, 35 i.e. 7 largest integer by which both the numbers can be divided.

Greatest common factor (GCF) of 21 and 35 is 7.

GCF(21,35) = 7

GCF of 21 and 35

Greatest common factor or Greatest common divisor (GCD) can be calculated in following way;

GCF of:
and

Greatest Common Factor of 21 and 35 by Prime factorization method

Prime Factorization of 21


3 21
7 7
1

Prime factors of 21 are 3,7. Prime factorization of 21 in exponential form is:

21 = 31×71

Prime Factorization of 35


5 35
7 7
1

Prime factors of 35 are 5,7. Prime factorization of 35 in exponential form is:

35 = 51×71

∴ So by taking common prime factors GCF of 21 and 35 is 7

Greatest Common Factor of 21 and 35 by matching factors method

Factors of 21

List of positive integer factors of 21 that divides 21 without a remainder.

1,3,7,21

Factors of 35

List of positive integer factors of 35 that divides 35 without a remainder.

1,5,7,35

Greatest Common Factor

We found the factors and prime factorization of 21 and 35. The biggest common factor number is the GCF number.
So the greatest common factor 21 and 35 is 7.

Also check out the Least Common Multiple of 21 and 35

Properties of GCF 21 and 35

(i) The GCF of 21 and 35 is associative

GCF of 21 and 35 = GCF of 35 and 21

Frequently Asked Questions on GCF of 21 and 35

1. What is the GCF of 21 and 35?

Answer: GCF of 21 and 35 is 7.

2. What are the Factors of 21?

Answer: Factors of 21 are 1, 3, 7, 21. There are 4 integers that are factors of 21. The greatest factor of 21 is 21.

3. What are the Factors of 35?

Answer: Factors of 35 are 1, 5, 7, 35. There are 4 integers that are factors of 35. The greatest factor of 35 is 35.

4. How to Find the GCF of 21 and 35?

Answer:

Greatest Common Factor of 21 and 35 = 7

Step 1: Find the prime factorization of 21

21 = 3 x 7

Step 2: Find the prime factorization of 35

35 = 5 x 7

Step 3: Multiply those factors both numbers have in common in steps i) or ii) above to find the gcf:

GCF = 7

Step 4: Therefore, the greatest common factor of 21 and 35 is 7