Just got sent this in an email.
It is said that engineers take 3 minutes to resolve this, architects 3 hours and doctors 6 hours (and bankers can't get it...) . If you guess which the 6th number is, you'll be able to open the excel file. Once you discover it, put in your name, save it and send it on...
Which is the 6th number?
1, 2, 6, 42, 1806, ___???
I got it right in a couple of minutes. But as I don't have excel I can't do much with the file. Well, I can save and open it with OO but can't then save with the password.