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What is the Least Common Multiple of 20820 and 20840?

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 20820 and 20840 is 21694440.

LCM(20820,20840) = 21694440

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Least Common Multiple of 20820 and 20840 with GCF Formula

The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 20820 and 20840, than apply into the LCM equation.

GCF(20820,20840) = 20
LCM(20820,20840) = ( 20820 × 20840) / 20
LCM(20820,20840) = 433888800 / 20
LCM(20820,20840) = 21694440

Least Common Multiple (LCM) of 20820 and 20840 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 20820 and 20840. First we will calculate the prime factors of 20820 and 20840.

Prime Factorization of 20820

Prime factors of 20820 are 2, 3, 5, 347. Prime factorization of 20820 in exponential form is:

20820 = 22 × 31 × 51 × 3471

Prime Factorization of 20840

Prime factors of 20840 are 2, 5, 521. Prime factorization of 20840 in exponential form is:

20840 = 23 × 51 × 5211

Now multiplying the highest exponent prime factors to calculate the LCM of 20820 and 20840.

LCM(20820,20840) = 23 × 31 × 51 × 3471 × 5211
LCM(20820,20840) = 21694440