What is the Greatest Common Factor of 644 and 660?

Greatest common factor (GCF) of 644 and 660 is 4.

GCF(644,660) = 4

We will now calculate the prime factors of 644 and 660, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 644 and 660.

How to find the GCF of 644 and 660?

We will first find the prime factorization of 644 and 660. After we will calculate the factors of 644 and 660 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 660

Prime factors of 660 are 2, 3, 5, 11. Prime factorization of 660 in exponential form is:

660 = 2² × 3¹ × 5¹ × 11¹

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 660

List of positive integer factors of 660 that divides 644 without a remainder.

1, 2, 3, 4, 5, 6, 10, 11, 12, 15, 20, 22, 30, 33, 44, 55, 60, 66, 110, 132, 165, 220, 330

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 644 and 660. The biggest common factor number is the GCF number.
So the greatest common factor 644 and 660 is 4.

Also check out the Least Common Multiple of 644 and 660