What is the Greatest Common Factor of 21090 and 21105?

Greatest common factor (GCF) of 21090 and 21105 is 15.

GCF(21090,21105) = 15

We will now calculate the prime factors of 21090 and 21105, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21090 and 21105.

How to find the GCF of 21090 and 21105?

We will first find the prime factorization of 21090 and 21105. After we will calculate the factors of 21090 and 21105 and find the biggest common factor number .

Step-1: Prime Factorization of 21090

Prime factors of 21090 are 2, 3, 5, 19, 37. Prime factorization of 21090 in exponential form is:

21090 = 2¹ × 3¹ × 5¹ × 19¹ × 37¹

Step-2: Prime Factorization of 21105

Prime factors of 21105 are 3, 5, 7, 67. Prime factorization of 21105 in exponential form is:

21105 = 3² × 5¹ × 7¹ × 67¹

Step-3: Factors of 21090

List of positive integer factors of 21090 that divides 21090 without a remainder.

1, 2, 3, 5, 6, 10, 15, 19, 30, 37, 38, 57, 74, 95, 111, 114, 185, 190, 222, 285, 370, 555, 570, 703, 1110, 1406, 2109, 3515, 4218, 7030, 10545

Step-4: Factors of 21105

List of positive integer factors of 21105 that divides 21090 without a remainder.

1, 3, 5, 7, 9, 15, 21, 35, 45, 63, 67, 105, 201, 315, 335, 469, 603, 1005, 1407, 2345, 3015, 4221, 7035

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21090 and 21105. The biggest common factor number is the GCF number.
So the greatest common factor 21090 and 21105 is 15.

Also check out the Least Common Multiple of 21090 and 21105