Excel – autoformatting number to formula

I have a file that is acting kinda funny. Maybe I am just an idiot. 🙂

In a Microsoft Excel 2000 WS, I have a column that includes 16 digit numbers such as: 4366163039281060 (exampple). Excel is automatically converting to 4.36616E+15 (example). This is only after I convert to.csv file and open it in Excel. The actual .csv file is fine. This wouldn’t be an issue, I am importing this to a program and it will be fine, but the executives do not understand this and want to see the file looking all pretty in Excel. If I save it to .xls, it looks fine. If I change the column to number format, it is fine until I save the .csv and reopen in Excel. If I open as .txt, it is fine as well.

I must be missing something very easy, but I have changed all of the settings I think may be effecting this, and I cannot get it to work.