SMO 2015 Open Round 1 Question 19

Let $x_1,x_2,x_3,x_4$ and $x_5$ be positive integers such that $$x_1+x_2+x_3+x_4+x_5=x_1\cdot x_2\cdot x_3\cdot x_4\cdot x_5.$$ Find the largest possible value of $x_5$.