# What is the Greatest Common Factor of 66 and 77?

Greatest common factor (GCF) of 66 and 77 is 11.

GCF(66,77) = 11

We will now calculate the prime factors of 66 and 77, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 66 and 77.

GCF Calculator and
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## How to find the GCF of 66 and 77?

We will first find the prime factorization of 66 and 77. After we will calculate the factors of 66 and 77 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 77

Prime factors of 77 are 7, 11. Prime factorization of 77 in exponential form is:

77 = 71 × 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 77

List of positive integer factors of 77 that divides 66 without a remainder.

1, 7, 11

#### Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 66 and 77. The biggest common factor number is the GCF number.
So the greatest common factor 66 and 77 is 11.

Also check out the Least Common Multiple of 66 and 77