What is the least common factor of 21 and 1?

To answer the question, "What is the least common factor of 21 and 1?", we will start by defining and listing factors of 21 and 1.

Factors of 21 are all the integers that when multiplied by another integer equal 21. Likewise, factors of 1 are all the integers that when multiplied by another integer equal 1.

The factors of 21 are 1, 3, 7, and 21.

The factors 1 are 1 and 1.

When you ask, "What is the least common factor of 21 and 1?", least is the key word here. Least means smallest. Thus, the smallest or least common factor that 21 and 1 have in common is 1.

Note that all integers, such as 21 and 1, have 1 as one of its factors. Thus, the answer to the least common factor of any two integers greater than 0 will always be 1.

Now that you know the least common factor of 21 and 1, you may also be interested in knowing the greatest common factor of 21 and 1. The greatest factor 21 and 1 have in common, per the list above, is 1.

When you asked for the least common factor of 21 and 1, did you mean least common multiple? If so, the least common multiple of 21 and 1 is 21.

Least Common Factor Calculator
Need the least common factor for another set of numbers? Please submit your numbers here:

What is the least common factor of 21 and 2?
Go here for the next least common factor problem on our list.