What is the Greatest Common Factor of 1605 and 1620?

Greatest common factor (GCF) of 1605 and 1620 is 15.

GCF(1605,1620) = 15

We will now calculate the prime factors of 1605 and 1620, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 1605 and 1620.

How to find the GCF of 1605 and 1620?

We will first find the prime factorization of 1605 and 1620. After we will calculate the factors of 1605 and 1620 and find the biggest common factor number .

Step-1: Prime Factorization of 1605

Prime factors of 1605 are 3, 5, 107. Prime factorization of 1605 in exponential form is:

1605 = 3¹ × 5¹ × 107¹

Step-2: Prime Factorization of 1620

Prime factors of 1620 are 2, 3, 5. Prime factorization of 1620 in exponential form is:

1620 = 2² × 3⁴ × 5¹

Step-3: Factors of 1605

List of positive integer factors of 1605 that divides 1605 without a remainder.

1, 3, 5, 15, 107, 321, 535

Step-4: Factors of 1620

List of positive integer factors of 1620 that divides 1605 without a remainder.

1, 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 27, 30, 36, 45, 54, 60, 81, 90, 108, 135, 162, 180, 270, 324, 405, 540, 810

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 1605 and 1620. The biggest common factor number is the GCF number.
So the greatest common factor 1605 and 1620 is 15.

Also check out the Least Common Multiple of 1605 and 1620