Least Common Multiple  of 21 and 25 is 525

How to find the Least Common Multiple of 21 and 25?

On this page below, we'll use the Prime Factorisation, and the List of Multiples method to find out the LCM of 21 and 25.

Follow the steps below, and let's calculate the LCM of 21 and 25.


Method 1 - Prime factorization

Step 1: Create a list of all the prime factors of the numbers 21 and 25:

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 25

The prime factors of 25 are 5 and 5. Prime factorization of 25 in exponential form is:

25 = 52


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

31, 71, 52


Step 3: Multiply these values together:

31x71x52=525


Step 4: The result:

As seen on the calculation above, we have now obtained the LCM of 21 and 25.

The Least Common Multiple of 21 and 25 is 525.


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, 315, 336, 357, 378, 399, 420, 441, 462, 483, 504, 525, 546, 567, 588

Multiples of 25:

25, 50, 75, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500, 525, 550, 575, 600


Therefore,

LCM(21, 25) = 525