88343532313733

This number is a prime.

                                                             8834 3532313733

The largest prime formed by inserting between the digits of the largest 2-digit prime ending with 3, (i.e., 83), a concatenation in some order of all the double-digit primes ending with 3, i.e., 83, 43, 53, 23, 13, 73. [Loungrides]