What is the Greatest Common Factor of 1215 and 1220?

Greatest common factor (GCF) of 1215 and 1220 is 5.

GCF(1215,1220) = 5

We will now calculate the prime factors of 1215 and 1220, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 1215 and 1220.

How to find the GCF of 1215 and 1220?

We will first find the prime factorization of 1215 and 1220. After we will calculate the factors of 1215 and 1220 and find the biggest common factor number .

Step-1: Prime Factorization of 1215

Prime factors of 1215 are 3, 5. Prime factorization of 1215 in exponential form is:

1215 = 3⁵ × 5¹

Step-2: Prime Factorization of 1220

Prime factors of 1220 are 2, 5, 61. Prime factorization of 1220 in exponential form is:

1220 = 2² × 5¹ × 61¹

Step-3: Factors of 1215

List of positive integer factors of 1215 that divides 1215 without a remainder.

1, 3, 5, 9, 15, 27, 45, 81, 135, 243, 405

Step-4: Factors of 1220

List of positive integer factors of 1220 that divides 1215 without a remainder.

1, 2, 4, 5, 10, 20, 61, 122, 244, 305, 610

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 1215 and 1220. The biggest common factor number is the GCF number.
So the greatest common factor 1215 and 1220 is 5.

Also check out the Least Common Multiple of 1215 and 1220