What is the Greatest Common Factor of 21979 and 21987?

Greatest common factor (GCF) of 21979 and 21987 is 1.

GCF(21979,21987) = 1

We will now calculate the prime factors of 21979 and 21987, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21979 and 21987.

How to find the GCF of 21979 and 21987?

We will first find the prime factorization of 21979 and 21987. After we will calculate the factors of 21979 and 21987 and find the biggest common factor number .

Step-1: Prime Factorization of 21979

Prime factors of 21979 are 31, 709. Prime factorization of 21979 in exponential form is:

21979 = 31¹ × 709¹

Step-2: Prime Factorization of 21987

Prime factors of 21987 are 3, 7, 349. Prime factorization of 21987 in exponential form is:

21987 = 3² × 7¹ × 349¹

Step-3: Factors of 21979

List of positive integer factors of 21979 that divides 21979 without a remainder.

1, 31, 709

Step-4: Factors of 21987

List of positive integer factors of 21987 that divides 21979 without a remainder.

1, 3, 7, 9, 21, 63, 349, 1047, 2443, 3141, 7329

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21979 and 21987. The biggest common factor number is the GCF number.
So the greatest common factor 21979 and 21987 is 1.

Also check out the Least Common Multiple of 21979 and 21987