What is the Greatest Common Factor of 1991 and 1997?

Greatest common factor (GCF) of 1991 and 1997 is 1.

GCF(1991,1997) = 1

We will now calculate the prime factors of 1991 and 1997, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 1991 and 1997.

How to find the GCF of 1991 and 1997?

We will first find the prime factorization of 1991 and 1997. After we will calculate the factors of 1991 and 1997 and find the biggest common factor number .

Step-1: Prime Factorization of 1991

Prime factors of 1991 are 11, 181. Prime factorization of 1991 in exponential form is:

1991 = 11¹ × 181¹

Step-2: Prime Factorization of 1997

Prime factors of 1997 are 1997. Prime factorization of 1997 in exponential form is:

1997 = 1997¹

Step-3: Factors of 1991

List of positive integer factors of 1991 that divides 1991 without a remainder.

1, 11, 181

Step-4: Factors of 1997

List of positive integer factors of 1997 that divides 1991 without a remainder.

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 1991 and 1997. The biggest common factor number is the GCF number.
So the greatest common factor 1991 and 1997 is 1.

Also check out the Least Common Multiple of 1991 and 1997