What is the Greatest Common Factor of 3920 and 3940?

Greatest common factor (GCF) of 3920 and 3940 is 20.

GCF(3920,3940) = 20

We will now calculate the prime factors of 3920 and 3940, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 3920 and 3940.

How to find the GCF of 3920 and 3940?

We will first find the prime factorization of 3920 and 3940. After we will calculate the factors of 3920 and 3940 and find the biggest common factor number .

Step-1: Prime Factorization of 3920

Prime factors of 3920 are 2, 5, 7. Prime factorization of 3920 in exponential form is:

3920 = 2⁴ × 5¹ × 7²

Step-2: Prime Factorization of 3940

Prime factors of 3940 are 2, 5, 197. Prime factorization of 3940 in exponential form is:

3940 = 2² × 5¹ × 197¹

Step-3: Factors of 3920

List of positive integer factors of 3920 that divides 3920 without a remainder.

1, 2, 4, 5, 7, 8, 10, 14, 16, 20, 28, 35, 40, 49, 56, 70, 80, 98, 112, 140, 196, 245, 280, 392, 490, 560, 784, 980, 1960

Step-4: Factors of 3940

List of positive integer factors of 3940 that divides 3920 without a remainder.

1, 2, 4, 5, 10, 20, 197, 394, 788, 985, 1970

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 3920 and 3940. The biggest common factor number is the GCF number.
So the greatest common factor 3920 and 3940 is 20.

Also check out the Least Common Multiple of 3920 and 3940