GCF for 20 and 405

What is the Greatest Common Factor of 20 and 405?

Answer: GCF of 20 and 405 is 5

(Five)

Finding GCF for 20 and 405 using all factors (divisors) listing

The first method to find GCF for numbers 20 and 405 is to list all factors for both numbers and pick the highest common one:

All factors of 20: 1, 2, 4, 5, 10, 20

All factors of 405: 1, 3, 5, 9, 15, 27, 45, 81, 135, 405

So the Greatest Common Factor for 20 and 405 is 5

Finding GCF for 20 and 405 by Prime Factorization

The second method to find GCF for numbers 20 and 405 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 20: 2, 2, 5

All Prime Factors of 405: 3, 3, 3, 3, 5

As we can see there is only one Prime Factor common to both numbers. It is 5

So 5 is the Greatest Common Factor of 20 and 405

GCF Table

Number 1Number 2GCF
54055
64053
74051
84051
94059
104055
114051
124053
134051
144051
1540515
164051
174051
184059
194051
204055
214053
224051
234051
244053
254055
264051
2740527
284051
294051
3040515
314051
324051
334053
344051

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 Factor of 20 and 405? (The answer is: 5). Select the first number (e.g. '20') and the second number (e.g. '405'). 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 Factor of 20 and 405?

GCF of 20 and 405 is 5