Least Common Multiple  of 13 and 21 is 273

How to find the Least Common Multiple of 13 and 21?

On this page below, we'll use the Prime Factorisation, and the List of Multiples method to find out the LCM of 13 and 21.

Follow the steps below, and let's calculate the LCM of 13 and 21.


Method 1 - Prime factorization

Step 1: Create a list of all the prime factors of the numbers 13 and 21:

Prime factors of 13

The prime factors of 13 are 13. Prime factorization of 13 in exponential form is:

13 = 131

Prime factors of 21

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

21 = 31x71


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

131, 31, 71


Step 3: Multiply these values together:

131x31x71=273


Step 4: The result:

As seen on the calculation above, we have now obtained the LCM of 13 and 21.

The Least Common Multiple of 13 and 21 is 273.


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 13:

13, 26, 39, 52, 65, 78, 91, 104, 117, 130, 143, 156, 169, 182, 195, 208, 221, 234, 247, 260, 273, 286, 299, 312

Multiples of 21:

21, 42, 63, 84, 105, 126, 147, 168, 189, 210, 231, 252, 273, 294, 315, 336


Therefore,

LCM(13, 21) = 273