What is the least common multiple of 54?

Short answer: There is none.

There is not a least common multiple of a single number, such as 54, because there cannot be any form of common multiple without two or more numbers to compare. Common multiples are multiples that the numbers being compared have in common. The least common multiple is the smallest multiple that all the numbers being compared have in common. Thus, since there are not two or more numbers to compare, there is not a least common multiple.

The lowest common multiple of 54 depends upon the other number(s) with which it has COMMON multiples and is one of the multiples of 54. The common multiples of 54 depends upon the other numbers with which 54 has COMMON multiples and are the multiples of the least common multiples between 54 and the other number(s).