735

This number is a composite.

There are exactly 735 Trotter primes less than 100,000,000. Note the first three odd primes in 735.

The smallest number concatenating its distinct prime factors: 735 = 7^2 * 3 * 5. [Post]

2^735+735 is a prime. Note that 735 is the only 3-digit composite number n such that 2^n+n is a prime. [Loungrides]