.. The pin code to Pierre's computer

As it is year 2037 now Patrick must have been born in year 2029.

So, you have a date of 6 of the second month year 2029. There are many ways you can present dates. Day first, month first, year first. You have time to try some.

Let's say Pierre doesn't use any date format that you should use when dealing with computers.

But he puts day first, then month, and the year last.

622029