What is the Greatest Common Factor of 21555 and 21570?

Greatest common factor (GCF) of 21555 and 21570 is 15.

GCF(21555,21570) = 15

We will now calculate the prime factors of 21555 and 21570, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21555 and 21570.

How to find the GCF of 21555 and 21570?

We will first find the prime factorization of 21555 and 21570. After we will calculate the factors of 21555 and 21570 and find the biggest common factor number .

Step-1: 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-2: Prime Factorization of 21570

Prime factors of 21570 are 2, 3, 5, 719. Prime factorization of 21570 in exponential form is:

21570 = 2¹ × 3¹ × 5¹ × 719¹

Step-3: Factors of 21555

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

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

Step-4: Factors of 21570

List of positive integer factors of 21570 that divides 21555 without a remainder.

1, 2, 3, 5, 6, 10, 15, 30, 719, 1438, 2157, 3595, 4314, 7190, 10785

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21555 and 21570. The biggest common factor number is the GCF number.
So the greatest common factor 21555 and 21570 is 15.

Also check out the Least Common Multiple of 21555 and 21570