138

138 = 2 x 3 x 23.

138 is the smallest possible product of 3 primes, one of which is the concatenation of the other two.

138 is a value of n for which n!!! - 1 is prime.

12 × 483 = 5,796 = 42 × 138.

NGC-138 is a spiral galaxy in the constellation Pisces.

Source: Number Gossip