What is the Greatest Common Factor of 21870 and 21885?

Greatest common factor (GCF) of 21870 and 21885 is 15.

GCF(21870,21885) = 15

We will now calculate the prime factors of 21870 and 21885, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21870 and 21885.

How to find the GCF of 21870 and 21885?

We will first find the prime factorization of 21870 and 21885. After we will calculate the factors of 21870 and 21885 and find the biggest common factor number .

Step-1: Prime Factorization of 21870

Prime factors of 21870 are 2, 3, 5. Prime factorization of 21870 in exponential form is:

21870 = 2¹ × 3⁷ × 5¹

Step-2: Prime Factorization of 21885

Prime factors of 21885 are 3, 5, 1459. Prime factorization of 21885 in exponential form is:

21885 = 3¹ × 5¹ × 1459¹

Step-3: Factors of 21870

List of positive integer factors of 21870 that divides 21870 without a remainder.

1, 2, 3, 5, 6, 9, 10, 15, 18, 27, 30, 45, 54, 81, 90, 135, 162, 243, 270, 405, 486, 729, 810, 1215, 1458, 2187, 2430, 3645, 4374, 7290, 10935

Step-4: Factors of 21885

List of positive integer factors of 21885 that divides 21870 without a remainder.

1, 3, 5, 15, 1459, 4377, 7295

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21870 and 21885. The biggest common factor number is the GCF number.
So the greatest common factor 21870 and 21885 is 15.

Also check out the Least Common Multiple of 21870 and 21885