What is the Greatest Common Factor of 21991 and 21998?

Greatest common factor (GCF) of 21991 and 21998 is 1.

GCF(21991,21998) = 1

We will now calculate the prime factors of 21991 and 21998, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21991 and 21998.

How to find the GCF of 21991 and 21998?

We will first find the prime factorization of 21991 and 21998. After we will calculate the factors of 21991 and 21998 and find the biggest common factor number .

Step-1: Prime Factorization of 21991

Prime factors of 21991 are 21991. Prime factorization of 21991 in exponential form is:

21991 = 21991¹

Step-2: Prime Factorization of 21998

Prime factors of 21998 are 2, 17, 647. Prime factorization of 21998 in exponential form is:

21998 = 2¹ × 17¹ × 647¹

Step-3: Factors of 21991

List of positive integer factors of 21991 that divides 21991 without a remainder.

Step-4: Factors of 21998

List of positive integer factors of 21998 that divides 21991 without a remainder.

1, 2, 17, 34, 647, 1294, 10999

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21991 and 21998. The biggest common factor number is the GCF number.
So the greatest common factor 21991 and 21998 is 1.

Also check out the Least Common Multiple of 21991 and 21998