What is the Least Common Multiple of 20640 and 20645?

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 20640 and 20645 with GCF Formula

The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 20640 and 20645, than apply into the LCM equation.

GCF(20640,20645) = 5
LCM(20640,20645) = ( 20640 × 20645) / 5
LCM(20640,20645) = 426112800 / 5
LCM(20640,20645) = 85222560

Least Common Multiple (LCM) of 20640 and 20645 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 20640 and 20645. First we will calculate the prime factors of 20640 and 20645.

Prime Factorization of 20640

Prime Factorization of 20645

Now multiplying the highest exponent prime factors to calculate the LCM of 20640 and 20645.

LCM(20640,20645) = 2⁵ × 3¹ × 5¹ × 43¹ × 4129¹
LCM(20640,20645) = 85222560