Date and time difference in Days, Hours, Mins

Date and time difference in Days, Hours, Mins

Hi,

I have a formula which calculates the difference between two date and time fields. It works, except I have it set so it only displays difference in hours and minutes. 

(((((((Task_Completed_Date_Time - Request_Date_Time)  /  (1000  *  3600))).toLong())) + " Hours ") + (((((((Task_Completed_Date_Time - Request_Date_Time)  /  (1000  *  3600))).toDecimal()  -  (((Task_Completed_Date_Time - Request_Date_Time)  /  (1000  *  3600))).toLong())  *  60)).toLong())) + " Mins"


What would I do to have it display in Days, Hours and Mins? 


Thank you in advance!


Joy