What is the Greatest Common Factor of 1281 and 1290?

Greatest common factor (GCF) of 1281 and 1290 is 3.

GCF(1281,1290) = 3

We will now calculate the prime factors of 1281 and 1290, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 1281 and 1290.

How to find the GCF of 1281 and 1290?

We will first find the prime factorization of 1281 and 1290. After we will calculate the factors of 1281 and 1290 and find the biggest common factor number .

Step-1: Prime Factorization of 1281

Prime factors of 1281 are 3, 7, 61. Prime factorization of 1281 in exponential form is:

1281 = 3¹ × 7¹ × 61¹

Step-2: Prime Factorization of 1290

Prime factors of 1290 are 2, 3, 5, 43. Prime factorization of 1290 in exponential form is:

1290 = 2¹ × 3¹ × 5¹ × 43¹

Step-3: Factors of 1281

List of positive integer factors of 1281 that divides 1281 without a remainder.

1, 3, 7, 21, 61, 183, 427

Step-4: Factors of 1290

List of positive integer factors of 1290 that divides 1281 without a remainder.

1, 2, 3, 5, 6, 10, 15, 30, 43, 86, 129, 215, 258, 430, 645

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 1281 and 1290. The biggest common factor number is the GCF number.
So the greatest common factor 1281 and 1290 is 3.

Also check out the Least Common Multiple of 1281 and 1290