Least Common Multiple  of 21 and 33 is 231

How to find the Least Common Multiple of 21 and 33?

On this page below, we'll use the Prime Factorisation, and the List of Multiples method to find out the LCM of 21 and 33.

Follow the steps below, and let's calculate the LCM of 21 and 33.


Method 1 - Prime factorization

Step 1: Create a list of all the prime factors of the numbers 21 and 33:

Prime factors of 21

The prime factors of 21 are 3 and 7. Prime factorization of 21 in exponential form is:

21 = 31x71

Prime factors of 33

The prime factors of 33 are 3 and 11. Prime factorization of 33 in exponential form is:

33 = 31x111


Step 2: Identify the highest power of each prime number from the above boxes:

31, 71, 111


Step 3: Multiply these values together:

31x71x111=231


Step 4: The result:

As seen on the calculation above, we have now obtained the LCM of 21 and 33.

The Least Common Multiple of 21 and 33 is 231.


Method 2 - List of Multiples

Find and list multiples of each number until the first common multiple is found. This is the lowest common multiple.


Multiples of 21:

21, 42, 63, 84, 105, 126, 147, 168, 189, 210, 231, 252, 273, 294

Multiples of 33:

33, 66, 99, 132, 165, 198, 231, 264, 297, 330


Therefore,

LCM(21, 33) = 231