What is the Greatest Common Factor of 21903 and 21915?

Greatest common factor (GCF) of 21903 and 21915 is 3.

GCF(21903,21915) = 3

We will now calculate the prime factors of 21903 and 21915, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21903 and 21915.

How to find the GCF of 21903 and 21915?

We will first find the prime factorization of 21903 and 21915. After we will calculate the factors of 21903 and 21915 and find the biggest common factor number .

Step-1: Prime Factorization of 21903

Prime factors of 21903 are 3, 7, 149. Prime factorization of 21903 in exponential form is:

21903 = 3¹ × 7² × 149¹

Step-2: Prime Factorization of 21915

Prime factors of 21915 are 3, 5, 487. Prime factorization of 21915 in exponential form is:

21915 = 3² × 5¹ × 487¹

Step-3: Factors of 21903

List of positive integer factors of 21903 that divides 21903 without a remainder.

1, 3, 7, 21, 49, 147, 149, 447, 1043, 3129, 7301

Step-4: Factors of 21915

List of positive integer factors of 21915 that divides 21903 without a remainder.

1, 3, 5, 9, 15, 45, 487, 1461, 2435, 4383, 7305

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21903 and 21915. The biggest common factor number is the GCF number.
So the greatest common factor 21903 and 21915 is 3.

Also check out the Least Common Multiple of 21903 and 21915