  In this article we study the number of different cuboids $\mathcal{O}(N)$
that can be built with an arbitrary number $N$ of equal cubes. This problem is
equivalent to find the number of different cuboids of volume $N$ with integer
length edges. We obtain an iterative method to calculate the value of
$\mathcal{O}(N)$ for any $N$. Using this method we obtain an explicit formula
when $N$ is the product of two powers of prime numbers. The bidimensional case
is also studied and we give a general formula to determine the number of
different rectangles that can be built with an arbitrary number of equal
squares.
