$\forall m,n \in \Bbb N$ : $\ 56786730\mid mn(m^{60}-n^{60})$
Hint $\ $ Apply little Fermat, noticing that $\rm\displaystyle\ 56786730\ = \!\!\prod_{\begin{array}\rm p\ prime\\ \rm p-1\mid\, 60\end{array}}\! p$
Hint $\ $ Apply little Fermat, noticing that $\rm\displaystyle\ 56786730\ = \!\!\prod_{\begin{array}\rm p\ prime\\ \rm p-1\mid\, 60\end{array}}\! p$