What is the Greatest Common Factor of 21891 and 21909?

Greatest common factor (GCF) of 21891 and 21909 is 3.

GCF(21891,21909) = 3

We will now calculate the prime factors of 21891 and 21909, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21891 and 21909.

How to find the GCF of 21891 and 21909?

We will first find the prime factorization of 21891 and 21909. After we will calculate the factors of 21891 and 21909 and find the biggest common factor number .

Step-1: Prime Factorization of 21891

Prime factors of 21891 are 3, 7297. Prime factorization of 21891 in exponential form is:

21891 = 3¹ × 7297¹

Step-2: Prime Factorization of 21909

Prime factors of 21909 are 3, 67, 109. Prime factorization of 21909 in exponential form is:

21909 = 3¹ × 67¹ × 109¹

Step-3: Factors of 21891

List of positive integer factors of 21891 that divides 21891 without a remainder.

1, 3, 7297

Step-4: Factors of 21909

List of positive integer factors of 21909 that divides 21891 without a remainder.

1, 3, 67, 109, 201, 327, 7303

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21891 and 21909. The biggest common factor number is the GCF number.
So the greatest common factor 21891 and 21909 is 3.

Also check out the Least Common Multiple of 21891 and 21909