What is the Greatest Common Factor of 20985 and 20991?

Greatest common factor (GCF) of 20985 and 20991 is 3.

GCF(20985,20991) = 3

We will now calculate the prime factors of 20985 and 20991, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 20985 and 20991.

How to find the GCF of 20985 and 20991?

We will first find the prime factorization of 20985 and 20991. After we will calculate the factors of 20985 and 20991 and find the biggest common factor number .

Step-1: Prime Factorization of 20985

Prime factors of 20985 are 3, 5, 1399. Prime factorization of 20985 in exponential form is:

20985 = 3¹ × 5¹ × 1399¹

Step-2: Prime Factorization of 20991

Prime factors of 20991 are 3, 6997. Prime factorization of 20991 in exponential form is:

20991 = 3¹ × 6997¹

Step-3: Factors of 20985

List of positive integer factors of 20985 that divides 20985 without a remainder.

1, 3, 5, 15, 1399, 4197, 6995

Step-4: Factors of 20991

List of positive integer factors of 20991 that divides 20985 without a remainder.

1, 3, 6997

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 20985 and 20991. The biggest common factor number is the GCF number.
So the greatest common factor 20985 and 20991 is 3.

Also check out the Least Common Multiple of 20985 and 20991