DECLARE @time int, @dt datetime;
SET @time = 80010;
SET @dt = DATEADD(second, 80010%100,DATEADD(minute, 80010%10000/100,DATEADD(hour, 80010/10000,'19000101')));

SELECT @dt

DECLARE @starttime int = 80010
	,@endtime int = 161500

SELECT ((@endtime/10000 * 60) + (@endtime%10000/100))
	- ((@starttime/10000 * 60) + (@starttime%10000/100))