What is the Greatest Common Factor of 6405 and 6420?

Greatest common factor (GCF) of 6405 and 6420 is 15.

GCF(6405,6420) = 15

We will now calculate the prime factors of 6405 and 6420, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 6405 and 6420.

How to find the GCF of 6405 and 6420?

We will first find the prime factorization of 6405 and 6420. After we will calculate the factors of 6405 and 6420 and find the biggest common factor number .

Step-1: Prime Factorization of 6405

Prime factors of 6405 are 3, 5, 7, 61. Prime factorization of 6405 in exponential form is:

6405 = 3¹ × 5¹ × 7¹ × 61¹

Step-2: Prime Factorization of 6420

Prime factors of 6420 are 2, 3, 5, 107. Prime factorization of 6420 in exponential form is:

6420 = 2² × 3¹ × 5¹ × 107¹

Step-3: Factors of 6405

List of positive integer factors of 6405 that divides 6405 without a remainder.

1, 3, 5, 7, 15, 21, 35, 61, 105, 183, 305, 427, 915, 1281, 2135

Step-4: Factors of 6420

List of positive integer factors of 6420 that divides 6405 without a remainder.

1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60, 107, 214, 321, 428, 535, 642, 1070, 1284, 1605, 2140, 3210

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 6405 and 6420. The biggest common factor number is the GCF number.
So the greatest common factor 6405 and 6420 is 15.

Also check out the Least Common Multiple of 6405 and 6420