What is the Greatest Common Factor of 20640 and 20655?

Greatest common factor (GCF) of 20640 and 20655 is 15.

GCF(20640,20655) = 15

We will now calculate the prime factors of 20640 and 20655, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 20640 and 20655.

How to find the GCF of 20640 and 20655?

We will first find the prime factorization of 20640 and 20655. After we will calculate the factors of 20640 and 20655 and find the biggest common factor number .

Step-1: Prime Factorization of 20640

Prime factors of 20640 are 2, 3, 5, 43. Prime factorization of 20640 in exponential form is:

20640 = 2⁵ × 3¹ × 5¹ × 43¹

Step-2: Prime Factorization of 20655

Prime factors of 20655 are 3, 5, 17. Prime factorization of 20655 in exponential form is:

20655 = 3⁵ × 5¹ × 17¹

Step-3: Factors of 20640

List of positive integer factors of 20640 that divides 20640 without a remainder.

1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 32, 40, 43, 48, 60, 80, 86, 96, 120, 129, 160, 172, 215, 240, 258, 344, 430, 480, 516, 645, 688, 860, 1032, 1290, 1376, 1720, 2064, 2580, 3440, 4128, 5160, 6880, 10320

Step-4: Factors of 20655

List of positive integer factors of 20655 that divides 20640 without a remainder.

1, 3, 5, 9, 15, 17, 27, 45, 51, 81, 85, 135, 153, 243, 255, 405, 459, 765, 1215, 1377, 2295, 4131, 6885

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 20640 and 20655. The biggest common factor number is the GCF number.
So the greatest common factor 20640 and 20655 is 15.

Also check out the Least Common Multiple of 20640 and 20655