# Greatest Common Factor of 81 and 85

Make use of GCF Calculator to quickly find the Greatest Common Factor of numbers 81, 85 i.e. 1 largest integer by which both the numbers can be divided.

Greatest common factor (GCF) of 81 and 85 is 1.

GCF(81,85) = 1

## GCF of 81 and 85

Greatest common factor or Greatest common divisor (GCD) can be calculated in following way;

GCF of:
and

### Greatest Common Factor of 81 and 85 by Prime factorization method

Prime Factorization of 81

 3 81 3 27 3 9 3 3 1

Prime factors of 81 are 3. Prime factorization of 81 in exponential form is:

81 = 34

Prime Factorization of 85

 5 85 17 17 1

Prime factors of 85 are 5.Prime factorization of 85 in exponential form is:

85 = 51×171

∴ So by taking common prime factors GCF of 81 and 85 is 1

### Greatest Common Factor of 81 and 85 by matching factors method

Factors of 81

List of positive integer factors of 81 that divides 81 without a remainder.

1,3,9,27,81

Factors of 85

List of positive integer factors of 85 that divides 85 without a remainder.

1,5,17,85

Greatest Common Factor

We found the factors and prime factorization of 81 and 85. The biggest common factor number is the GCF number.
So the greatest common factor 81 and 85 is 1.

Also check out the Least Common Multiple of 81 and 85

### Properties of GCF 81 and 85

(i) The GCF of 81 and 85 is associative

GCF of 81 and 85 = GCF of 85 and 81

### Frequently Asked Questions on GCF of 81 and 85

1. What is the GCF of 81 and 85?

Answer: GCF of 81 and 85 is 1.

2. What are the Factors of 81?

Answer: Factors of 81 are 1, 3, 9, 27, 81. There are 5 integers that are factors of 81. The greatest factor of 81 is 81.

3. What are the Factors of 85?

Answer: Factors of 85 are 1, 5, 17, 85. There are 4 integers that are factors of 85. The greatest factor of 85 is 85.

4. How to Find the GCF of 81 and 85?

Answer:

Greatest Common Factor of 81 and 85 = 1

Step 1: Find the prime factorization of 81

81 = 3 x 3 x 3 x 3

Step 2: Find the prime factorization of 85

85 = 5 x 17

Step 3: Multiply those factors both numbers have in common in steps i) or ii) above to find the gcf:

GCF = = 1

Step 4: Therefore, the greatest common factor of 81 and 85 is 1