6723

6723 = 3 x 3 x 3 x 3 x 83.

6723 is a value of n for which 3n and 8n together use each digit from 0 to 9 exactly once.

6723 is 25413 in base 7.

6723 is the solution to the postage stamp problem with 3 denominations and 47 stamps (A001208).

6723 is the maximum number of points visible from some point in a cubic 20 x 20 x 20 lattice (A141227).

Source: What's Special About This Number?