What is the Greatest Common Factor of 1985 and 1991?

Greatest common factor (GCF) of 1985 and 1991 is 1.

GCF(1985,1991) = 1

We will now calculate the prime factors of 1985 and 1991, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 1985 and 1991.

How to find the GCF of 1985 and 1991?

We will first find the prime factorization of 1985 and 1991. After we will calculate the factors of 1985 and 1991 and find the biggest common factor number .

Step-1: Prime Factorization of 1985

Prime factors of 1985 are 5, 397. Prime factorization of 1985 in exponential form is:

1985 = 5¹ × 397¹

Step-2: Prime Factorization of 1991

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

1991 = 11¹ × 181¹

Step-3: Factors of 1985

List of positive integer factors of 1985 that divides 1985 without a remainder.

1, 5, 397

Step-4: Factors of 1991

List of positive integer factors of 1991 that divides 1985 without a remainder.

1, 11, 181

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 1985 and 1991. The biggest common factor number is the GCF number.
So the greatest common factor 1985 and 1991 is 1.

Also check out the Least Common Multiple of 1985 and 1991