What is the Greatest Common Factor of 21505 and 21510?

Greatest common factor (GCF) of 21505 and 21510 is 5.

GCF(21505,21510) = 5

We will now calculate the prime factors of 21505 and 21510, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21505 and 21510.

How to find the GCF of 21505 and 21510?

We will first find the prime factorization of 21505 and 21510. After we will calculate the factors of 21505 and 21510 and find the biggest common factor number .

Step-1: Prime Factorization of 21505

Prime factors of 21505 are 5, 11, 17, 23. Prime factorization of 21505 in exponential form is:

21505 = 5¹ × 11¹ × 17¹ × 23¹

Step-2: Prime Factorization of 21510

Prime factors of 21510 are 2, 3, 5, 239. Prime factorization of 21510 in exponential form is:

21510 = 2¹ × 3² × 5¹ × 239¹

Step-3: Factors of 21505

List of positive integer factors of 21505 that divides 21505 without a remainder.

1, 5, 11, 17, 23, 55, 85, 115, 187, 253, 391, 935, 1265, 1955, 4301

Step-4: Factors of 21510

List of positive integer factors of 21510 that divides 21505 without a remainder.

1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90, 239, 478, 717, 1195, 1434, 2151, 2390, 3585, 4302, 7170, 10755

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21505 and 21510. The biggest common factor number is the GCF number.
So the greatest common factor 21505 and 21510 is 5.

Also check out the Least Common Multiple of 21505 and 21510