716539

This number is a composite.

The largest 2-sphenic number, i.e., 716539 = 83 x 89 x 97, consists of distinct digits. Note that a concatenation of its prime factors, i.e., 899783, creates a 4-almost prime (899783 = 19*23*29*97) with double-digit prime factors as well. [Loungrides]