What is the Greatest Common Factor of 21690 and 21705?

Greatest common factor (GCF) of 21690 and 21705 is 15.

GCF(21690,21705) = 15

We will now calculate the prime factors of 21690 and 21705, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21690 and 21705.

How to find the GCF of 21690 and 21705?

We will first find the prime factorization of 21690 and 21705. After we will calculate the factors of 21690 and 21705 and find the biggest common factor number .

Step-1: Prime Factorization of 21690

Prime factors of 21690 are 2, 3, 5, 241. Prime factorization of 21690 in exponential form is:

21690 = 2¹ × 3² × 5¹ × 241¹

Step-2: Prime Factorization of 21705

Prime factors of 21705 are 3, 5, 1447. Prime factorization of 21705 in exponential form is:

21705 = 3¹ × 5¹ × 1447¹

Step-3: Factors of 21690

List of positive integer factors of 21690 that divides 21690 without a remainder.

1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90, 241, 482, 723, 1205, 1446, 2169, 2410, 3615, 4338, 7230, 10845

Step-4: Factors of 21705

List of positive integer factors of 21705 that divides 21690 without a remainder.

1, 3, 5, 15, 1447, 4341, 7235

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21690 and 21705. The biggest common factor number is the GCF number.
So the greatest common factor 21690 and 21705 is 15.

Also check out the Least Common Multiple of 21690 and 21705