What is the Greatest Common Factor of 644 and 664?

Greatest common factor (GCF) of 644 and 664 is 4.

GCF(644,664) = 4

We will now calculate the prime factors of 644 and 664, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 644 and 664.

How to find the GCF of 644 and 664?

We will first find the prime factorization of 644 and 664. After we will calculate the factors of 644 and 664 and find the biggest common factor number .

Step-1: Prime Factorization of 644

Prime factors of 644 are 2, 7, 23. Prime factorization of 644 in exponential form is:

644 = 2² × 7¹ × 23¹

Step-2: Prime Factorization of 664

Prime factors of 664 are 2, 83. Prime factorization of 664 in exponential form is:

664 = 2³ × 83¹

Step-3: Factors of 644

List of positive integer factors of 644 that divides 644 without a remainder.

1, 2, 4, 7, 14, 23, 28, 46, 92, 161, 322

Step-4: Factors of 664

List of positive integer factors of 664 that divides 644 without a remainder.

1, 2, 4, 8, 83, 166, 332

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 644 and 664. The biggest common factor number is the GCF number.
So the greatest common factor 644 and 664 is 4.

Also check out the Least Common Multiple of 644 and 664