What is the Greatest Common Factor of 21970 and 21981?

Greatest common factor (GCF) of 21970 and 21981 is 1.

GCF(21970,21981) = 1

We will now calculate the prime factors of 21970 and 21981, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21970 and 21981.

How to find the GCF of 21970 and 21981?

We will first find the prime factorization of 21970 and 21981. After we will calculate the factors of 21970 and 21981 and find the biggest common factor number .

Step-1: Prime Factorization of 21970

Prime factors of 21970 are 2, 5, 13. Prime factorization of 21970 in exponential form is:

21970 = 2¹ × 5¹ × 13³

Step-2: Prime Factorization of 21981

Prime factors of 21981 are 3, 17, 431. Prime factorization of 21981 in exponential form is:

21981 = 3¹ × 17¹ × 431¹

Step-3: Factors of 21970

List of positive integer factors of 21970 that divides 21970 without a remainder.

1, 2, 5, 10, 13, 26, 65, 130, 169, 338, 845, 1690, 2197, 4394, 10985

Step-4: Factors of 21981

List of positive integer factors of 21981 that divides 21970 without a remainder.

1, 3, 17, 51, 431, 1293, 7327

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21970 and 21981. The biggest common factor number is the GCF number.
So the greatest common factor 21970 and 21981 is 1.

Also check out the Least Common Multiple of 21970 and 21981