What is the Greatest Common Factor of 840 and 857?

Greatest common factor (GCF) of 840 and 857 is 1.

GCF(840,857) = 1

We will now calculate the prime factors of 840 and 857, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 840 and 857.

How to find the GCF of 840 and 857?

We will first find the prime factorization of 840 and 857. After we will calculate the factors of 840 and 857 and find the biggest common factor number .

Step-1: Prime Factorization of 840

Prime factors of 840 are 2, 3, 5, 7. Prime factorization of 840 in exponential form is:

840 = 2³ × 3¹ × 5¹ × 7¹

Step-2: Prime Factorization of 857

Prime factors of 857 are 857. Prime factorization of 857 in exponential form is:

857 = 857¹

Step-3: Factors of 840

List of positive integer factors of 840 that divides 840 without a remainder.

1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 15, 20, 21, 24, 28, 30, 35, 40, 42, 56, 60, 70, 84, 105, 120, 140, 168, 210, 280, 420

Step-4: Factors of 857

List of positive integer factors of 857 that divides 840 without a remainder.

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 840 and 857. The biggest common factor number is the GCF number.
So the greatest common factor 840 and 857 is 1.

Also check out the Least Common Multiple of 840 and 857