What is the Greatest Common Factor of 291 and 309?

Greatest common factor (GCF) of 291 and 309 is 3.

GCF(291,309) = 3

We will now calculate the prime factors of 291 and 309, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 291 and 309.

How to find the GCF of 291 and 309?

We will first find the prime factorization of 291 and 309. After we will calculate the factors of 291 and 309 and find the biggest common factor number .

Step-1: Prime Factorization of 291

Prime factors of 291 are 3, 97. Prime factorization of 291 in exponential form is:

291 = 3¹ × 97¹

Step-2: Prime Factorization of 309

Prime factors of 309 are 3, 103. Prime factorization of 309 in exponential form is:

309 = 3¹ × 103¹

Step-3: Factors of 291

List of positive integer factors of 291 that divides 291 without a remainder.

1, 3, 97

Step-4: Factors of 309

List of positive integer factors of 309 that divides 291 without a remainder.

1, 3, 103

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 291 and 309. The biggest common factor number is the GCF number.
So the greatest common factor 291 and 309 is 3.

Also check out the Least Common Multiple of 291 and 309