GCD of 664, 636, 21, 645 Calculator

Given Input numbers are 664, 636, 21, 645

To find the GCD of numbers using factoring list out all the divisors of each number

Divisors of 664

List of positive integer divisors of 664 that divides 664 without a remainder.

1, 2, 4, 8, 83, 166, 332, 664

Divisors of 636

List of positive integer divisors of 636 that divides 636 without a remainder.

1, 2, 3, 4, 6, 12, 53, 106, 159, 212, 318, 636

Divisors of 21

List of positive integer divisors of 21 that divides 21 without a remainder.

1, 3, 7, 21

Divisors of 645

List of positive integer divisors of 645 that divides 645 without a remainder.

1, 3, 5, 15, 43, 129, 215, 645

Greatest Common Divisior

We found the divisors of 664, 636, 21, 645 . The biggest common divisior number is the GCD number.
So the Greatest Common Divisior 664, 636, 21, 645 is 1.

Therefore, GCD of numbers 664, 636, 21, 645 is 1

Given Input Data is 664, 636, 21, 645

Make a list of Prime Factors of all the given numbers initially

Prime Factorization of 664 is 2 x 2 x 2 x 83

Prime Factorization of 636 is 2 x 2 x 3 x 53

Prime Factorization of 21 is 3 x 7

Prime Factorization of 645 is 3 x 5 x 43

The above numbers do not have any common prime factor. So GCD is 1

Step1:

Let's calculate the GCD of first two numbers

The formula of GCD is GCD(a, b) = ( a x b) / LCM(a, b)

LCM(664, 636) = 105576

GCD(664, 636) = ( 664 x 636 ) / 105576

GCD(664, 636) = 422304 / 105576

GCD(664, 636) = 4

Step2:

Here we consider the GCD from the above i.e. 4 as first number and the next as 21

The formula of GCD is GCD(a, b) = ( a x b) / LCM(a, b)

LCM(4, 21) = 84

GCD(4, 21) = ( 4 x 21 ) / 84

GCD(4, 21) = 84 / 84

GCD(4, 21) = 1

Step3:

Here we consider the GCD from the above i.e. 1 as first number and the next as 645

The formula of GCD is GCD(a, b) = ( a x b) / LCM(a, b)

LCM(1, 645) = 645

GCD(1, 645) = ( 1 x 645 ) / 645

GCD(1, 645) = 645 / 645

GCD(1, 645) = 1

GCD of 664, 636, 21, 645 is 1

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1. What is the GCD of 664, 636, 21, 645?

GCD of 664, 636, 21, 645 is 1

2. Where do I get the detailed procedure to find GCD of 664, 636, 21, 645?

You can find a detailed procedure to find GCD of 664, 636, 21, 645 on our page.

3. How to find GCD of 664, 636, 21, 645 on a calculator?

You can find the GCD of 664, 636, 21, 645 by simply giving the inputs separated by commas and click on the calculate button to avail the Greatest Common Divisor in less time.