A number of the form which contains the digits 666 (the Beast Number) is called an Apocalyptic Number. is an apocalyptic number. The first few such powers are 157, 192, 218, 220, ... (Sloane's A007356).
See also Apocalypse Number, Leviathan Number
References
Pickover, C. A. Keys to Infinity. New York: Wiley, pp. 97-102, 1995.
Sloane, N. J. A. Sequence
A007356/M5405
in ``An On-Line Version of the Encyclopedia of Integer Sequences.''
http://www.research.att.com/~njas/sequences/eisonline.html and extended entry in
Sloane, N. J. A. and Plouffe, S.
The Encyclopedia of Integer Sequences. San Diego: Academic Press, 1995.