What is the Greatest Common Factor of 21861 and 21879?

Greatest common factor (GCF) of 21861 and 21879 is 9.

GCF(21861,21879) = 9

We will now calculate the prime factors of 21861 and 21879, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21861 and 21879.

How to find the GCF of 21861 and 21879?

We will first find the prime factorization of 21861 and 21879. After we will calculate the factors of 21861 and 21879 and find the biggest common factor number .

Step-1: Prime Factorization of 21861

Prime factors of 21861 are 3, 7, 347. Prime factorization of 21861 in exponential form is:

21861 = 3² × 7¹ × 347¹

Step-2: Prime Factorization of 21879

Prime factors of 21879 are 3, 11, 13, 17. Prime factorization of 21879 in exponential form is:

21879 = 3² × 11¹ × 13¹ × 17¹

Step-3: Factors of 21861

List of positive integer factors of 21861 that divides 21861 without a remainder.

1, 3, 7, 9, 21, 63, 347, 1041, 2429, 3123, 7287

Step-4: Factors of 21879

List of positive integer factors of 21879 that divides 21861 without a remainder.

1, 3, 9, 11, 13, 17, 33, 39, 51, 99, 117, 143, 153, 187, 221, 429, 561, 663, 1287, 1683, 1989, 2431, 7293

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21861 and 21879. The biggest common factor number is the GCF number.
So the greatest common factor 21861 and 21879 is 9.

Also check out the Least Common Multiple of 21861 and 21879