What is the Greatest Common Factor of 155 and 165?

Greatest common factor (GCF) of 155 and 165 is 5.

GCF(155,165) = 5

We will now calculate the prime factors of 155 and 165, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 155 and 165.

How to find the GCF of 155 and 165?

We will first find the prime factorization of 155 and 165. After we will calculate the factors of 155 and 165 and find the biggest common factor number .

Step-1: Prime Factorization of 155

Prime factors of 155 are 5, 31. Prime factorization of 155 in exponential form is:

155 = 5¹ × 31¹

Step-2: Prime Factorization of 165

Prime factors of 165 are 3, 5, 11. Prime factorization of 165 in exponential form is:

165 = 3¹ × 5¹ × 11¹

Step-3: Factors of 155

List of positive integer factors of 155 that divides 155 without a remainder.

1, 5, 31

Step-4: Factors of 165

List of positive integer factors of 165 that divides 155 without a remainder.

1, 3, 5, 11, 15, 33, 55

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 155 and 165. The biggest common factor number is the GCF number.
So the greatest common factor 155 and 165 is 5.

Also check out the Least Common Multiple of 155 and 165