LCM for 21 and 45

"Least Common Multiple" Calculator

Least Common Multiple of

and

What's the Least Common Multiple (LCM) of 21 and 45?

Answer

LCM of 21 and 45 is 315

(Three hundred fifteen)

Finding LCM for 21 and 45 using GCF of these numbers

The first method to find LCM for numbers 21 and 45 is to find Greatest Common Factor (GCF) of these numbers. Here's the formula:

LCM = (Number1 × Number2) ÷ GCF

GCF of numbers 21 and 45 is 3, so

LCM = (21 × 45) ÷ 3

LCM = 945 ÷ 3

LCM = 315

Finding LCM for 21 and 45 by Listing Multiples

The second method to find LCM for numbers 21 and 45 is to list out the common multiples for both numbers and pick the first one that matches:

Multiples of 21: 21, 42, 63, 84, 105, 126, 147, 168, 189, 210, 231, 252, 273, 294, 315, 336, 357

Multiples of 45: 45, 90, 135, 180, 225, 270, 315, 360, 405

So the LCM for 21 and 45 is 315

Finding LCM for 21 and 45 by Prime Factorization

Another method to find LCM for numbers 21 and 45 is to list all Prime Factors for both numbers and multiply the highest exponent prime factors:

All Prime Factors of 21: 3, 7 (exponent form: 31, 71)

All Prime Factors of 45: 3, 3, 5 (exponent form: 32, 51)

32 × 71 × 51 = 315

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About "Least Common Multiple" Calculator

This calculator will help you find the Least Common Multiple (LCM) of two numbers. For example, it can help you find out what's the Least Common Multiple (LCM) of 21 and 45? (The answer is: 315). Select the first number (e.g. '21') and the second number (e.g. '45'). After that hit the 'Calculate' button.
Least Common Multiple (LCM) also known as the Lowest Common Multiple or Smallest Common Multiple of 2 numbers - it is the smallest positive integer that is divisible by both numbers

"Least Common Multiple" Calculator

Least Common Multiple of

and

LCM Table

Number 1Number 2LCM
64590
745315
845360
94545
104590
1145495
1245180
1345585
1445630
154545
1645720
1745765
184590
1945855
2045180
2145315
2245990
23451035
2445360
2545225
26451170
2745135
28451260
29451305
304590
31451395
32451440
3345495
34451530
3545315

FAQ

What's the Least Common Multiple (LCM) of 21 and 45?

LCM of 21 and 45 is 315

How to find the LCM of 21 and 45 using prime factorization?

To find the LCM of 21 and 45, find all prime factors of both numbers, then multiply the highest power of each prime factor. The result is 315.

What is the difference between LCM and GCF?

LCM (Least Common Multiple) is the smallest number divisible by both numbers, while GCF (Greatest Common Factor) is the largest number that divides both. For 21 and 45: LCM = 315, GCF = 3.

See Also