What is the Greatest Common Factor of 21957 and 21970?

Greatest common factor (GCF) of 21957 and 21970 is 13.

GCF(21957,21970) = 13

We will now calculate the prime factors of 21957 and 21970, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21957 and 21970.

How to find the GCF of 21957 and 21970?

We will first find the prime factorization of 21957 and 21970. After we will calculate the factors of 21957 and 21970 and find the biggest common factor number .

Step-1: Prime Factorization of 21957

Prime factors of 21957 are 3, 13, 563. Prime factorization of 21957 in exponential form is:

21957 = 3¹ × 13¹ × 563¹

Step-2: Prime Factorization of 21970

Prime factors of 21970 are 2, 5, 13. Prime factorization of 21970 in exponential form is:

21970 = 2¹ × 5¹ × 13³

Step-3: Factors of 21957

List of positive integer factors of 21957 that divides 21957 without a remainder.

1, 3, 13, 39, 563, 1689, 7319

Step-4: Factors of 21970

List of positive integer factors of 21970 that divides 21957 without a remainder.

1, 2, 5, 10, 13, 26, 65, 130, 169, 338, 845, 1690, 2197, 4394, 10985

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21957 and 21970. The biggest common factor number is the GCF number.
So the greatest common factor 21957 and 21970 is 13.

Also check out the Least Common Multiple of 21957 and 21970