Are All Perfect Numbers Even?

Open Question
By the Theorem of Even Perfect Numbers, it is known that an even number is perfect it is of the form:
 * $2^{n-1} \left({2^n - 1}\right)$

where $2^n - 1$ is prime.

It is not known whether there exist any odd perfect numbers. None have ever been found.

However, it is known that no odd perfect number contains less than 100 digits.