What is the Greatest Common Factor of 665 and 670?

Greatest common factor (GCF) of 665 and 670 is 5.

GCF(665,670) = 5

We will now calculate the prime factors of 665 and 670, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 665 and 670.

How to find the GCF of 665 and 670?

We will first find the prime factorization of 665 and 670. After we will calculate the factors of 665 and 670 and find the biggest common factor number .

Step-1: Prime Factorization of 665

Prime factors of 665 are 5, 7, 19. Prime factorization of 665 in exponential form is:

665 = 5¹ × 7¹ × 19¹

Step-2: Prime Factorization of 670

Prime factors of 670 are 2, 5, 67. Prime factorization of 670 in exponential form is:

670 = 2¹ × 5¹ × 67¹

Step-3: Factors of 665

List of positive integer factors of 665 that divides 665 without a remainder.

1, 5, 7, 19, 35, 95, 133

Step-4: Factors of 670

List of positive integer factors of 670 that divides 665 without a remainder.

1, 2, 5, 10, 67, 134, 335

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 665 and 670. The biggest common factor number is the GCF number.
So the greatest common factor 665 and 670 is 5.

Also check out the Least Common Multiple of 665 and 670