A beastly day.
660
Approximate number of the Beast

DCLXVI
Roman numeral of the Beast

666.0000
Number of the High Precision Beast

0.666
Number of the Millibeast

0.00000000000000000000000000000000000666
Number of the Nanobeast

/ 666
Beast Common Denominator

(-666) ^ (1/2)
Imaginary number of the Beast

6.66 e3
Floating point Beast

1010011010
Binary of the Beast

6, uh... what was that number again?
Number of the Blonde Beast

1-666
Area code of the Beast

00666
Zip code of the Beast

666mph
The speed limit of the Beast

$665.95
Retail price of the Beast

$699.25
Price of the Beast plus 5% state sales tax

$769.95
Price of the Beast with all accessories and replacement soul

$656.66
Walmart price of the Beast

$646.66
Next week's Walmart price of the Beast

Phillips 666
Gasoline of the Beast

Route 666
Way of the Beast

666 F
Oven temperature for roast Beast

666k
Retirement plan of the Beast

666 mg
Recommended Minimum Daily Requirement of Beast

6.66 %
5 year CD interest rate at First Beast of Hell National Bank, $666 minimum deposit.

$666/hr
Beast's lawyer's billing rate

Lotus 6-6-6
Spreadsheet of the Beast

Word 6.66
Word Processor of the Beast

i66686
CPU of the Beast

665.9997856
The Number of the Beast on a Pentium

666i
BMW of the Beast

DSM-666 (revised)
Diagnostic and Statistical Manual of the Beast

1232 Octal, Apt. 29A
Beast's hexed address

668
Next-door neighbor of the Beast

333
The semi-Christ

I wish I could say I made this up.