Is there a formula that I can use to calculate a date/time from a number based on the fixed date of January 1, 1601?

If this sounds familiar to you, you'll know that I'm trying to convert a large integer into a date/time format. In this case, I'm exporting users from a domain controller and trying to view the LastLogonTime variable that's only recorded as a large integer. If you're really nerdy, here's the gist of the topic.

http://www.microsoft.com/technet/scr...lastlogon.mspx

Anyway, I've done enough of the calculations in Excel to convert the variable into days. Now I just need to finish it by converting this number into a date/time.

Say, for example: I have one instance calculated to 147851.966 days. Now I need to determine what date/time this is based off of a January 01, 1601 start date.

Confusing enough?