8128 is a perfect number. A "Perfect" number, a positive integer that is equal to the sum of its proper divisors. The smallest perfect number is 6, which is the sum of 1, 2, and 3. Other perfect numbers are 28, 496, and 8,128. If you are fascinated by numbers (you are, right?) then you might be interested in seeing the type 1 with serial number 8128.

I wonder where it is?

You can see an auction of it here from 2003 when it sold for $599/£352:

http://www.christies.com/lotfinder/Lot/a-curta-calculator-type-i-4163896-details.aspx

All it said was "A Curta Calculator, Type I No. 8128, with eight slides, black finish and leather holder, in carton with instructions " with an image (lot 491)

I've got a Curta which is close by: 8121

Regards

Sebastian