LCM for 21 and 57

What's the Least Common Multiple (LCM) of 21 and 57?

Answer: LCM of 21 and 57 is 399

(Three hundred ninety-nine)

Finding LCM for 21 and 57 using GCF's of these numbers

The first method to find LCM for numbers 21 and 57 is to find Greatest Common Factor (GCF) of these numbers. Here's the formula:

LCM = (Number1 × Number2) ÷ GCF

GCF of numbers 21 and 57 is 3, so

LCM = (21 × 57) ÷ 3

LCM = 1197 ÷ 3

LCM = 399

Finding LCM for 21 and 57 by Listing Multiples

The second method to find LCM for numbers 21 and 57 is to list out the common multiples for both nubmers and pick the first which matching:

Multiples of 21: 21, 42, 63, 84, 105, 126, 147, 168, 189, 210, 231, 252, 273, 294, 315, 336, 357, 378, 399, 420, 441

Multiples of 57: 57, 114, 171, 228, 285, 342, 399, 456, 513

So the LCM for 21 and 57 is 399

Finding LCM for 21 and 57 by Prime Factorization

Another method to find LCM for numbers 21 and 57 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 57: 3, 19 (exponent form: 31, 191)

31 × 71 × 191 = 399

Related Calculations

See Also

LCM Table

Number 1Number 2LCM
657114
757399
857456
957171
1057570
1157627
1257228
1357741
1457798
1557285
1657912
1757969
1857342
1957
20571140
2157399
22571254
23571311
2457456
25571425
26571482
2757513
28571596
29571653
3057570
31571767
32571824
3357627
34571938
35571995

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 57? (The answer is: 399). Select the first number (e.g. '21') and the second number (e.g. '57'). 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

FAQ

What's the Least Common Multiple (LCM) of 21 and 57?

LCM of 21 and 57 is 399