Minimal numbers (A007416): let A(h) = least positive integer having exactly h divisors, let d(n) = number of divisors of n; then n is minimal if A(d(n)) = n; i.e. if n is the least positive integer having the number of divisors it has.
Also the numbers n such that LCM (1, ..., n) is a highly composite number (A002182). - Matthew Vandermast, Jul 12 2004
REFERENCES
J. Roberts, Lure of the Integers, Math. Assoc. of America, 1992, page 86.
