GCF for 21 and 140

What is the Greatest common Divisor of 21 and 140?

Answer: GCF of 21 and 140 is 7

(Seven)

Finding GCF for 21 and 140 using all factors (divisors) listing

The first method to find GCF for numbers 21 and 140 is to list all factors for both numbers and pick the highest common one:

All factors of 21: 1, 3, 7, 21

All factors of 140: 1, 2, 4, 5, 7, 10, 14, 20, 28, 35, 70, 140

So the Greatest Common Factor for 21 and 140 is 7

Finding GCF for 21 and 140 by Prime Factorization

The second method to find GCF for numbers 21 and 140 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 21: 3, 7

All Prime Factors of 140: 2, 2, 5, 7

As we can see there is only one Prime Factor common to both numbers. It is 7

So 7 is the Greatest Common Factor of 21 and 140

See Also

About "Greatest Common Factor" Calculator

This calculator will help you find the greatest common factor (GCF) of two numbers. For example, it can help you find out what is the Greatest common Divisor of 21 and 140? (The answer is: 7). Select the first number (e.g. '21') and the second number (e.g. '140'). After that hit the 'Calculate' button.
Greatest Common Factor (GCF) also known as the Greatest Common Divisor (GCD) or Highest Common Factor (HCF) - it is the largest positive integer that divides each of the integers with zero remainder

GCF Table

Number 1Number 2GCF
61402
71407
81404
91401
1014010
111401
121404
131401
1414014
151405
161404
171401
181402
191401
2014020
21140
221402
231401
241404
251405
261402
271401
2814028
291401
3014010
311401
321404
331401
341402
3514035

FAQ

What is the Greatest common Divisor of 21 and 140?

GCF of 21 and 140 is 7