What is the Greatest Common Factor of 21543 and 21561?

Greatest common factor (GCF) of 21543 and 21561 is 3.

GCF(21543,21561) = 3

We will now calculate the prime factors of 21543 and 21561, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21543 and 21561.

How to find the GCF of 21543 and 21561?

We will first find the prime factorization of 21543 and 21561. After we will calculate the factors of 21543 and 21561 and find the biggest common factor number .

Step-1: Prime Factorization of 21543

Prime factors of 21543 are 3, 43, 167. Prime factorization of 21543 in exponential form is:

21543 = 3¹ × 43¹ × 167¹

Step-2: Prime Factorization of 21561

Prime factors of 21561 are 3, 7187. Prime factorization of 21561 in exponential form is:

21561 = 3¹ × 7187¹

Step-3: Factors of 21543

List of positive integer factors of 21543 that divides 21543 without a remainder.

1, 3, 43, 129, 167, 501, 7181

Step-4: Factors of 21561

List of positive integer factors of 21561 that divides 21543 without a remainder.

1, 3, 7187

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21543 and 21561. The biggest common factor number is the GCF number.
So the greatest common factor 21543 and 21561 is 3.

Also check out the Least Common Multiple of 21543 and 21561