What is the Greatest Common Factor of 138 and 155?

Greatest common factor (GCF) of 138 and 155 is 1.

GCF(138,155) = 1

We will now calculate the prime factors of 138 and 155, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 138 and 155.

How to find the GCF of 138 and 155?

We will first find the prime factorization of 138 and 155. After we will calculate the factors of 138 and 155 and find the biggest common factor number .

Step-1: Prime Factorization of 138

Prime factors of 138 are 2, 3, 23. Prime factorization of 138 in exponential form is:

138 = 2¹ × 3¹ × 23¹

Step-2: Prime Factorization of 155

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

155 = 5¹ × 31¹

Step-3: Factors of 138

List of positive integer factors of 138 that divides 138 without a remainder.

1, 2, 3, 6, 23, 46, 69

Step-4: Factors of 155

List of positive integer factors of 155 that divides 138 without a remainder.

1, 5, 31

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 138 and 155. The biggest common factor number is the GCF number.
So the greatest common factor 138 and 155 is 1.

Also check out the Least Common Multiple of 138 and 155