How many factors has 1?

Answer 1

Good question. The short answer is "No," but there is some disagreement. Some people include 1, others do not. Part of the trouble comes from some countries that use the term "factor," others that use the term "divisor," and others which use them interchangeably. If I ruled the world, or even the math portion of it, here's what I would decree:

A proper factor of a positive integer N is a factor of N other than 1 or N.

For example, 2 and 3 are positive proper factors of 6, but 1 and 6 are not.

Compare with the term proper divisor, which means a factor of N other than N (but including 1).

Answer 2

One has one distinct factor: 1

Answer 3

1 has one factor.

Answer 4

One has no proper factors.