GCD of 661, 408, 21 Calculator

Given Input numbers are 661, 408, 21

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

Divisors of 661

List of positive integer divisors of 661 that divides 661 without a remainder.

1, 661

Divisors of 408

List of positive integer divisors of 408 that divides 408 without a remainder.

1, 2, 3, 4, 6, 8, 12, 17, 24, 34, 51, 68, 102, 136, 204, 408

Divisors of 21

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

1, 3, 7, 21

Greatest Common Divisior

We found the divisors of 661, 408, 21 . The biggest common divisior number is the GCD number.
So the Greatest Common Divisior 661, 408, 21 is 1.

Therefore, GCD of numbers 661, 408, 21 is 1

Given Input Data is 661, 408, 21

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

Prime Factorization of 661 is 661

Prime Factorization of 408 is 2 x 2 x 2 x 3 x 17

Prime Factorization of 21 is 3 x 7

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(661, 408) = 269688

GCD(661, 408) = ( 661 x 408 ) / 269688

GCD(661, 408) = 269688 / 269688

GCD(661, 408) = 1

Step2:

Here we consider the GCD from the above i.e. 1 as first number and the next as 21

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

LCM(1, 21) = 21

GCD(1, 21) = ( 1 x 21 ) / 21

GCD(1, 21) = 21 / 21

GCD(1, 21) = 1

GCD of 661, 408, 21 is 1

Here are some samples of GCD of Numbers calculations.

• GCD of 616, 740, 32
• GCD of 880, 652, 97
• GCD of 391, 686, 70
• GCD of 716, 225, 83
• GCD of 112, 104, 25

1. What is the GCD of 661, 408, 21?

GCD of 661, 408, 21 is 1

2. Where do I get the detailed procedure to find GCD of 661, 408, 21?

You can find a detailed procedure to find GCD of 661, 408, 21 on our page.

3. How to find GCD of 661, 408, 21 on a calculator?

You can find the GCD of 661, 408, 21 by simply giving the inputs separated by commas and click on the calculate button to avail the Greatest Common Divisor in less time.