# What is the Least Common Multiple of 39 and 51?

*Least common multiple* or lowest common denominator (lcd) can be calculated in two way; with the LCM formula calculation of greatest common factor (GCF), or multiplying the prime factors with the highest exponent factor.

Least common multiple (LCM) of 39 and 51 is **663**.

LCM(39,51) = 663

## Least Common Multiple of 39 and 51 with GCF Formula

The formula of **LCM** is LCM(a,b) = ( a × b) / GCF(a,b).

We need to calculate greatest common factor 39 and 51, than apply into the LCM equation.

GCF(39,51) = 3

LCM(39,51) = ( 39 × 51) / 3

LCM(39,51) = 1989 / 3

LCM(39,51) = 663

## Least Common Multiple (LCM) of 39 and 51 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 39 and 51. First we will calculate the **prime factors of 39 and 51**.

### Prime Factorization of 39

Prime factors of 39 are 3, 13. Prime factorization of **39** in exponential form is:

39 = 3^{1} × 13^{1}

### Prime Factorization of 51

Prime factors of 51 are 3, 17. Prime factorization of **51** in exponential form is:

51 = 3^{1} × 17^{1}

Now multiplying the highest exponent prime factors to calculate the **LCM of 39 and 51**.

LCM(39,51) = 3^{1} × 13^{1} × 17^{1}

LCM(39,51) = 663