GCF for 21 and 126

What is the Greatest common Divisor of 21 and 126?

Answer: GCF of 21 and 126 is 21

(Twenty-one)

Finding GCF for 21 and 126 using all factors (divisors) listing

The first method to find GCF for numbers 21 and 126 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 126: 1, 2, 3, 6, 7, 9, 14, 18, 21, 42, 63, 126

So the Greatest Common Factor for 21 and 126 is 21

Finding GCF for 21 and 126 by Prime Factorization

The second method to find GCF for numbers 21 and 126 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 126: 2, 3, 3, 7

As we can see there are Prime Factors common to both numbers: 3, 7

Now we need to multiply them to find GCF: 3 × 7 = 21

See Also

GCF Table

Number 1Number 2GCF
61266
71267
81262
91269
101262
111261
121266
131261
1412614
151263
161262
171261
1812618
191261
201262
21126
221262
231261
241266
251261
261262
271269
2812614
291261
301266
311261
321262
331263
341262
351267

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 126? (The answer is: 21). Select the first number (e.g. '21') and the second number (e.g. '126'). 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

FAQ

What is the Greatest common Divisor of 21 and 126?

GCF of 21 and 126 is 21