7481

This number is a prime.

The largest emirp whose adjacent digit differences form an emirp (i.e., |7-4|=3; |4-8|=4; |8-1|=7; 347 is emirp) whose adjacent digit differences also form another emirp (i.e., 13), whose digit difference forms a prime (i.e., 2) and whose emirp also has this characteristic (i.e., 1847 forms 743 which forms 31 which forms 2). [Opao]