prove tha there is no prime number p such that $\displaystyle p^{2} -81 $ is divisible by 54.

suppose $\displaystyle 54/ p^{2} - 81 $

than

$\displaystyle p^{2} -81 = 54K $ for some K in the naturals.

how would I proceed from here? very confused, I am suppose to come up with some sort of contradiction.

any help appreciated.