What is the Greatest Common Factor of 1981 and 1985?

Greatest common factor (GCF) of 1981 and 1985 is 1.

GCF(1981,1985) = 1

We will now calculate the prime factors of 1981 and 1985, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 1981 and 1985.

How to find the GCF of 1981 and 1985?

We will first find the prime factorization of 1981 and 1985. After we will calculate the factors of 1981 and 1985 and find the biggest common factor number .

Step-1: Prime Factorization of 1981

Prime factors of 1981 are 7, 283. Prime factorization of 1981 in exponential form is:

1981 = 7¹ × 283¹

Step-2: Prime Factorization of 1985

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

1985 = 5¹ × 397¹

Step-3: Factors of 1981

List of positive integer factors of 1981 that divides 1981 without a remainder.

1, 7, 283

Step-4: Factors of 1985

List of positive integer factors of 1985 that divides 1981 without a remainder.

1, 5, 397

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 1981 and 1985. The biggest common factor number is the GCF number.
So the greatest common factor 1981 and 1985 is 1.

Also check out the Least Common Multiple of 1981 and 1985