Problem

Source: JBMO Shortlist 2023, N4

Tags: JBMO, JBMO Shortlist, number theory



The triangle $ABC$ is sectioned by $AD,BE$ and $CF$ (where $D \in (BC), E \in (CA)$ and $F \in (AB)$) in seven disjoint polygons named regions. In each one of the nine vertices of these regions we write a digit, such that each nonzero digit appears exactly once. We assign to each side of a region the lowest common multiple of the digits at its ends, and to each region the greatest common divisor of the numbers assigned to its sides. Find the largest possible value of the product of the numbers assigned to the regions.