What is the Least Common Multiple of 1605 and 1620?

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 of 1605 and 1620 with GCF Formula

The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 1605 and 1620, than apply into the LCM equation.

GCF(1605,1620) = 15
LCM(1605,1620) = ( 1605 × 1620) / 15
LCM(1605,1620) = 2600100 / 15
LCM(1605,1620) = 173340

Least Common Multiple (LCM) of 1605 and 1620 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 1605 and 1620. First we will calculate the prime factors of 1605 and 1620.

Prime Factorization of 1605

Prime Factorization of 1620

Now multiplying the highest exponent prime factors to calculate the LCM of 1605 and 1620.

LCM(1605,1620) = 3⁴ × 5¹ × 107¹ × 2²
LCM(1605,1620) = 173340