What is the Least Common Multiple of 621 and 640?

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 621 and 640 with GCF Formula

The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 621 and 640, than apply into the LCM equation.

GCF(621,640) = 1
LCM(621,640) = ( 621 × 640) / 1
LCM(621,640) = 397440 / 1
LCM(621,640) = 397440

Least Common Multiple (LCM) of 621 and 640 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 621 and 640. First we will calculate the prime factors of 621 and 640.

Prime Factorization of 621

Prime Factorization of 640

Now multiplying the highest exponent prime factors to calculate the LCM of 621 and 640.

LCM(621,640) = 3³ × 23¹ × 2⁷ × 5¹
LCM(621,640) = 397440