# Greatest Common Factor of 21 and 40

Greatest common factor (GCF) of 21 and 40 is **1**.

GCF(21,40) = 1

We will now calculate the prime factors of **21 and 40**, than find the greatest common factor *(greatest common divisor (gcd))* of the numbers by matching the biggest common factor of 21 and 40.

## Prime Factorization of 21

Prime factors of 21 are 3, 7. Prime factorization of **21** in exponential form is:

21 = 3^{1} × 7^{1}

## Prime Factorization of 40

Prime factors of 40 are 2, 5. Prime factorization of **40** in exponential form is:

40 = 2^{3} × 5^{1}

### Factors of 21

List of positive integer factors of 21 that divides 21 without a remainder.

1, 3, 7

### Factors of 40

List of positive integer factors of 40 that divides 21 without a remainder.

1, 2, 4, 5, 8, 10, 20

### Greatest Common Factor

We found the factors and prime factorization of 21 and 40. The biggest common factor number is the **GCF** number.

So the **greatest common factor 21 and 40** is **1**.

Also check out the Least Common Multiple of 21 and 40

## Recent Comments

THIS DOES NOT WORK