For example, oracle uses1970/01/01as the starting point of time, and the integer of 10000 is to add 10000 seconds to this starting point of time.
So far ('1970/01/01','yyyy/mm/DD')+10000/24/60/60.
Date addition and subtraction in oracle is in days, so it will be calculated later.
If you use C#
Datetime.minvalue.addseconds (10000), you can get the time after the initial date10000 seconds.
Other software has other ways of writing.