What is the Greatest Common Factor of 21240 and 21255?

Greatest common factor (GCF) of 21240 and 21255 is 15.

GCF(21240,21255) = 15

We will now calculate the prime factors of 21240 and 21255, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21240 and 21255.

How to find the GCF of 21240 and 21255?

We will first find the prime factorization of 21240 and 21255. After we will calculate the factors of 21240 and 21255 and find the biggest common factor number .

Step-1: Prime Factorization of 21240

Prime factors of 21240 are 2, 3, 5, 59. Prime factorization of 21240 in exponential form is:

21240 = 2³ × 3² × 5¹ × 59¹

Step-2: Prime Factorization of 21255

Prime factors of 21255 are 3, 5, 13, 109. Prime factorization of 21255 in exponential form is:

21255 = 3¹ × 5¹ × 13¹ × 109¹

Step-3: Factors of 21240

List of positive integer factors of 21240 that divides 21240 without a remainder.

1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 59, 60, 72, 90, 118, 120, 177, 180, 236, 295, 354, 360, 472, 531, 590, 708, 885, 1062, 1180, 1416, 1770, 2124, 2360, 2655, 3540, 4248, 5310, 7080, 10620

Step-4: Factors of 21255

List of positive integer factors of 21255 that divides 21240 without a remainder.

1, 3, 5, 13, 15, 39, 65, 109, 195, 327, 545, 1417, 1635, 4251, 7085

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21240 and 21255. The biggest common factor number is the GCF number.
So the greatest common factor 21240 and 21255 is 15.

Also check out the Least Common Multiple of 21240 and 21255