datetime in integer

Select @dt = GETDATE()
Select CONVERT(varchar(26),@dt, 121)
, CONVERT(bigint, replace(replace(replace(replace(convert(varchar(23),@dt,121),'-',''),':',''),'.',''),' ',''))
, CONVERT(int, @dt) -- date offset starting 1899-12-31
, DATEADD( D, -(CONVERT(int, @dt) ), @dt)