53537257

This number is a prime.

7*11*13*31*37*41 + 2*3*5*17*19*23*29 = 53537257 . The arithmetic expression in the left side A+B = P, for P= 53537257 uses all the primes from 2 to 41 and 53537257 is the largest composite integer with only and all four prime digits. By Anton Vrba. [Rivera]