Let $A_1A_2A_3A_4$ be a cyclic quadrilateral such that $A_1A_2=A_2A_3=A_3A_1$. Let $A_1A_3$ and $A_4A_2$ intersect at $A_5$. Given $A_2A_5=19$ and $A_5A_4=6$.  Find the product of possible values of $A_1A_4$.