Converting integer milliseconds value to date time format in sql server

I have a column called start time which is populated with a number like "1465815600000" and increasing. This column is the number of milliseconds from the year 1970 jan 1st 12.00:00:000 AM to a certain date in june 2016. This is in integer, which I need to convert it to date time format.

EX: 1465815600000 => 2016-06-12-12:00:00 (something like this)

Can somebody help me with to write this function?