【Question 4】Prime numbers are like the "building blocks" of natural numbers; every natural number can be written as the product of several primes (which may be the same), for example, $4=2 \times 2, 6=2 \times 3, 8=2 \times 2 \times 2, 9=3 \times 3, 10=2 \times 5$, etc. Therefore, $5 \times 13 \times 31-2$ written in this form is
$$
\begin{array}{l}
5 \times 13 \times 31-2=2015-2=2013 \\
2013=3 \times 11 \times 61
\end{array}
$$

Translation:
$$
\begin{array}{l}
5 \times 13 \times 31-2=2015-2=2013 \\
2013=3 \times 11 \times 61
\end{array}
$$