What is the Greatest Common Factor of 21540 and 21555?

Greatest common factor (GCF) of 21540 and 21555 is 15.

GCF(21540,21555) = 15

We will now calculate the prime factors of 21540 and 21555, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21540 and 21555.

How to find the GCF of 21540 and 21555?

We will first find the prime factorization of 21540 and 21555. After we will calculate the factors of 21540 and 21555 and find the biggest common factor number .

Step-1: Prime Factorization of 21540

Prime factors of 21540 are 2, 3, 5, 359. Prime factorization of 21540 in exponential form is:

21540 = 2² × 3¹ × 5¹ × 359¹

Step-2: Prime Factorization of 21555

Prime factors of 21555 are 3, 5, 479. Prime factorization of 21555 in exponential form is:

21555 = 3² × 5¹ × 479¹

Step-3: Factors of 21540

List of positive integer factors of 21540 that divides 21540 without a remainder.

1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60, 359, 718, 1077, 1436, 1795, 2154, 3590, 4308, 5385, 7180, 10770

Step-4: Factors of 21555

List of positive integer factors of 21555 that divides 21540 without a remainder.

1, 3, 5, 9, 15, 45, 479, 1437, 2395, 4311, 7185

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21540 and 21555. The biggest common factor number is the GCF number.
So the greatest common factor 21540 and 21555 is 15.

Also check out the Least Common Multiple of 21540 and 21555