What date format is 636529536000000000?

Question

I have to maintain an ASPX page that increments the date/time by passing a value in the querystring in this format:

636529536000000000 in reference to 31 January 2018

636530400000000000 in reference to 01 February 2018

The url format is: /reservas.aspx?t=636530400000000000

What is this date/time format?

Answer 1

It is the number of ticks where a tick is one hundred nanoseconds or one ten-millionth of a second. The number of ticks is measured since the epoch DateTime.MinValue (12:00:00 midnight, January 1, 0001). For example:

new DateTime(636529536000000000).ToString("F", CultureInfo.InvariantCulture)

outputs:

Wednesday, 31 January 2018 00:00:00

Answer 2

Could be a number of days from certain date, similar to julian date calculation:

https://en.wikipedia.org/wiki/Julian_day#Julian_date_calculation

Potentially incorporating the time as well?

Without details of the code I cant really advise from a provided value.