What is the Greatest Common Factor of 640 and 656?

Greatest common factor (GCF) of 640 and 656 is 16.

GCF(640,656) = 16

We will now calculate the prime factors of 640 and 656, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 640 and 656.

How to find the GCF of 640 and 656?

We will first find the prime factorization of 640 and 656. After we will calculate the factors of 640 and 656 and find the biggest common factor number .

Step-1: Prime Factorization of 640

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

640 = 2⁷ × 5¹

Step-2: Prime Factorization of 656

Prime factors of 656 are 2, 41. Prime factorization of 656 in exponential form is:

656 = 2⁴ × 41¹

Step-3: Factors of 640

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

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

Step-4: Factors of 656

List of positive integer factors of 656 that divides 640 without a remainder.

1, 2, 4, 8, 16, 41, 82, 164, 328

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 640 and 656. The biggest common factor number is the GCF number.
So the greatest common factor 640 and 656 is 16.

Also check out the Least Common Multiple of 640 and 656