# What is the Greatest Common Factor of 28 and 45?

Greatest common factor (GCF) of 28 and 45 is 1.

GCF(28,45) = 1

We will now calculate the prime factors of 28 and 45, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 28 and 45.

GCF Calculator and
and

## How to find the GCF of 28 and 45?

We will first find the prime factorization of 28 and 45. After we will calculate the factors of 28 and 45 and find the biggest common factor number .

### Step-1: Prime Factorization of 28

Prime factors of 28 are 2, 7. Prime factorization of 28 in exponential form is:

28 = 22 × 71

### Step-2: Prime Factorization of 45

Prime factors of 45 are 3, 5. Prime factorization of 45 in exponential form is:

45 = 32 × 51

### Step-3: Factors of 28

List of positive integer factors of 28 that divides 28 without a remainder.

1, 2, 4, 7, 14

### Step-4: Factors of 45

List of positive integer factors of 45 that divides 28 without a remainder.

1, 3, 5, 9, 15

#### Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 28 and 45. The biggest common factor number is the GCF number.
So the greatest common factor 28 and 45 is 1.

Also check out the Least Common Multiple of 28 and 45

#### Related Greatest Common Factors of 45

##### Recent Comments
Jannat 2019-08-15 09:16:23

I can't find the HCF of this number .......

Bad at Math 2018-05-21 20:19:04

Wow... I spent all that time trying to figure this out but turns out he GCF is 1.

Please share your comments