What is the Greatest Common Factor of 66 and 99?

Greatest common factor (GCF) of 66 and 99 is 33.

GCF(66,99) = 33

We will now calculate the prime factors of 66 and 99, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 66 and 99.

How to find the GCF of 66 and 99?

We will first find the prime factorization of 66 and 99. After we will calculate the factors of 66 and 99 and find the biggest common factor number .

Step-1: Prime Factorization of 66

Prime factors of 66 are 2, 3, 11. Prime factorization of 66 in exponential form is:

66 = 2¹ × 3¹ × 11¹

Step-2: Prime Factorization of 99

Prime factors of 99 are 3, 11. Prime factorization of 99 in exponential form is:

99 = 3² × 11¹

Step-3: Factors of 66

List of positive integer factors of 66 that divides 66 without a remainder.

1, 2, 3, 6, 11, 22, 33

Step-4: Factors of 99

List of positive integer factors of 99 that divides 66 without a remainder.

1, 3, 9, 11, 33

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 66 and 99. The biggest common factor number is the GCF number.
So the greatest common factor 66 and 99 is 33.

Also check out the Least Common Multiple of 66 and 99