Formatting dates as dates in Access

I'm embarrassed with a seemingly very simple problem. I have about 7 million of rows in Access, with a date column formatted as numbers. They are the 5 digit type of numbers excel uses when dates are formatted as numbers. How do I reformat them as dates?

For example, in access:

should look like (in Excel):

I tried using the built in date and time functions in Access to no avail. I can't simply move the database to Excel, reformat, then move on with my life due to the number of rows I'm using.

I wouldn't post this unless I thought other people would refer back to this and lea something.