GCF for 15 and 57

What is the Greatest common Divisor of 15 and 57?

Answer: GCF of 15 and 57 is 3

(Three)

Finding GCF for 15 and 57 using all factors (divisors) listing

The first method to find GCF for numbers 15 and 57 is to list all factors for both numbers and pick the highest common one:

All factors of 15: 1, 3, 5, 15

All factors of 57: 1, 3, 19, 57

So the Greatest Common Factor for 15 and 57 is 3

Finding GCF for 15 and 57 by Prime Factorization

The second method to find GCF for numbers 15 and 57 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 15: 3, 5

All Prime Factors of 57: 3, 19

As we can see there is only one Prime Factor common to both numbers. It is 3

So 3 is the Greatest Common Factor of 15 and 57

Related Calculations

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 15 and 57? (The answer is: 3). Select the first number (e.g. '15') and the second number (e.g. '57'). 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
1571
2571
3573
4571
5571
6573
7571
8571
9573
10571
11571
12573
13571
14571
1557
16571
17571
18573
1957
20571
21573
22571
23571
24573
25571
26571
2757
28571
29571
30573

FAQ

What is the Greatest common Divisor of 15 and 57?

GCF of 15 and 57 is 3