What is the Greatest Common Factor of 1561 and 1580?

Greatest common factor (GCF) of 1561 and 1580 is 1.

GCF(1561,1580) = 1

We will now calculate the prime factors of 1561 and 1580, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 1561 and 1580.

How to find the GCF of 1561 and 1580?

We will first find the prime factorization of 1561 and 1580. After we will calculate the factors of 1561 and 1580 and find the biggest common factor number .

Step-1: Prime Factorization of 1561

Prime factors of 1561 are 7, 223. Prime factorization of 1561 in exponential form is:

1561 = 7¹ × 223¹

Step-2: Prime Factorization of 1580

Prime factors of 1580 are 2, 5, 79. Prime factorization of 1580 in exponential form is:

1580 = 2² × 5¹ × 79¹

Step-3: Factors of 1561

List of positive integer factors of 1561 that divides 1561 without a remainder.

1, 7, 223

Step-4: Factors of 1580

List of positive integer factors of 1580 that divides 1561 without a remainder.

1, 2, 4, 5, 10, 20, 79, 158, 316, 395, 790

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 1561 and 1580. The biggest common factor number is the GCF number.
So the greatest common factor 1561 and 1580 is 1.

Also check out the Least Common Multiple of 1561 and 1580