What is the Greatest Common Factor of 21780 and 21785?

Greatest common factor (GCF) of 21780 and 21785 is 5.

GCF(21780,21785) = 5

We will now calculate the prime factors of 21780 and 21785, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21780 and 21785.

How to find the GCF of 21780 and 21785?

We will first find the prime factorization of 21780 and 21785. After we will calculate the factors of 21780 and 21785 and find the biggest common factor number .

Step-1: Prime Factorization of 21780

Prime factors of 21780 are 2, 3, 5, 11. Prime factorization of 21780 in exponential form is:

21780 = 2² × 3² × 5¹ × 11²

Step-2: Prime Factorization of 21785

Prime factors of 21785 are 5, 4357. Prime factorization of 21785 in exponential form is:

21785 = 5¹ × 4357¹

Step-3: Factors of 21780

List of positive integer factors of 21780 that divides 21780 without a remainder.

1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 15, 18, 20, 22, 30, 33, 36, 44, 45, 55, 60, 66, 90, 99, 110, 121, 132, 165, 180, 198, 220, 242, 330, 363, 396, 484, 495, 605, 660, 726, 990, 1089, 1210, 1452, 1815, 1980, 2178, 2420, 3630, 4356, 5445, 7260, 10890

Step-4: Factors of 21785

List of positive integer factors of 21785 that divides 21780 without a remainder.

1, 5, 4357

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21780 and 21785. The biggest common factor number is the GCF number.
So the greatest common factor 21780 and 21785 is 5.

Also check out the Least Common Multiple of 21780 and 21785