What is the Greatest Common Factor of 620 and 640?

Greatest common factor (GCF) of 620 and 640 is 20.

GCF(620,640) = 20

We will now calculate the prime factors of 620 and 640, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 620 and 640.

How to find the GCF of 620 and 640?

We will first find the prime factorization of 620 and 640. After we will calculate the factors of 620 and 640 and find the biggest common factor number .

Step-1: Prime Factorization of 620

Prime factors of 620 are 2, 5, 31. Prime factorization of 620 in exponential form is:

620 = 2² × 5¹ × 31¹

Step-2: Prime Factorization of 640

Prime factors of 640 are 2, 5. Prime factorization of 640 in exponential form is:

640 = 2⁷ × 5¹

Step-3: Factors of 620

List of positive integer factors of 620 that divides 620 without a remainder.

1, 2, 4, 5, 10, 20, 31, 62, 124, 155, 310

Step-4: Factors of 640

List of positive integer factors of 640 that divides 620 without a remainder.

1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 620 and 640. The biggest common factor number is the GCF number.
So the greatest common factor 620 and 640 is 20.

Also check out the Least Common Multiple of 620 and 640