# Factors of a number.

If $M$ is an even number.

Then what are the possible even factors of $M$ ?

I am thinking that maximum possible even factors are $\frac M2,\frac M4,\frac M8, \frac M{16}$ and so on Are there any even factors other than that ?

Am I correct ?

If $M=30$, then $M/2=15$ is not an even factor of $M$; however $2$, $6$, $10$, and $30$ are.
In fact, if $M=2^ns$, where $s$ is odd, then the even factors of $M$ are $2^mt$, where $1\le m\le n$ and $t$ is any factor of $s$.