546

546 = 2 x 3 x 7 x 13.

546 is 666 in base 9 and 222 in base 16.

546 is 202020 in base 3, 20202 in base 4, and 4141 in base 5.

546! - 1 is a prime number.

The sum 273 + 546 = 819 is one of only four cases in which the equality n + 2n= 3n uses each of the nine digits from 1 to 9.

BS 546 is an old British standard for domestic air conditioner power plugs and sockets.

Source: Prime Curios!