What is the Greatest Common Factor of 555 and 561?

Greatest common factor (GCF) of 555 and 561 is 3.

GCF(555,561) = 3

We will now calculate the prime factors of 555 and 561, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 555 and 561.

How to find the GCF of 555 and 561?

We will first find the prime factorization of 555 and 561. After we will calculate the factors of 555 and 561 and find the biggest common factor number .

Step-1: Prime Factorization of 555

Prime factors of 555 are 3, 5, 37. Prime factorization of 555 in exponential form is:

555 = 3¹ × 5¹ × 37¹

Step-2: Prime Factorization of 561

Prime factors of 561 are 3, 11, 17. Prime factorization of 561 in exponential form is:

561 = 3¹ × 11¹ × 17¹

Step-3: Factors of 555

List of positive integer factors of 555 that divides 555 without a remainder.

1, 3, 5, 15, 37, 111, 185

Step-4: Factors of 561

List of positive integer factors of 561 that divides 555 without a remainder.

1, 3, 11, 17, 33, 51, 187

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 555 and 561. The biggest common factor number is the GCF number.
So the greatest common factor 555 and 561 is 3.

Also check out the Least Common Multiple of 555 and 561