What is the Greatest Common Factor of 21428 and 21440?

Greatest common factor (GCF) of 21428 and 21440 is 4.

GCF(21428,21440) = 4

We will now calculate the prime factors of 21428 and 21440, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21428 and 21440.

How to find the GCF of 21428 and 21440?

We will first find the prime factorization of 21428 and 21440. After we will calculate the factors of 21428 and 21440 and find the biggest common factor number .

Step-1: Prime Factorization of 21428

Prime factors of 21428 are 2, 11, 487. Prime factorization of 21428 in exponential form is:

21428 = 2² × 11¹ × 487¹

Step-2: Prime Factorization of 21440

Prime factors of 21440 are 2, 5, 67. Prime factorization of 21440 in exponential form is:

21440 = 2⁶ × 5¹ × 67¹

Step-3: Factors of 21428

List of positive integer factors of 21428 that divides 21428 without a remainder.

1, 2, 4, 11, 22, 44, 487, 974, 1948, 5357, 10714

Step-4: Factors of 21440

List of positive integer factors of 21440 that divides 21428 without a remainder.

1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 67, 80, 134, 160, 268, 320, 335, 536, 670, 1072, 1340, 2144, 2680, 4288, 5360, 10720

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21428 and 21440. The biggest common factor number is the GCF number.
So the greatest common factor 21428 and 21440 is 4.

Also check out the Least Common Multiple of 21428 and 21440