In honor of that:
668: Neighbor of the beast.
1-888-666-6666: "the Toll-Free Number of the Beast"
$665.99: "the Retail Price of the Beast"
00666: "the ZIP Code of the Beast"
0.666: "the Number of the Millibeast"
Route 666: "the highway of the Beast"
6.5013:"the natural logarithm of the Beast"
333: the devil doing a half-hearted job,
Which makes √666 = 25.8068 the square root of all evil.
Additional numbers of the beast I thought of today after reading Joel's comment:
666EZ - The Tax form of the Beast
000666-0000666 - Docket number of the Beast's Divorce from Mrs. Beast
664 - The other neighbor of the beast.
667 - the sequal to the beast
Max Factor 666 soft black - the Mascara of the Beast
Beverly Hills, 90666 - The teen drama of the Beast
∏666 0r 2,091.25 - the Circumference of the Beast
TI666 - the Graphing Calculator of the Beast
666 Monkeys - The depressing Science Fiction movie of the Beast
666 Math, 666 Verbal - The SAT scores of the beast
Windows 666 - The Operating System of the Beast
867-5666 - The booty call of the Beast.