you can have a integer and a string in the prim's description, just seperate the two with a marker like a comma and just do llCSV2List
ie. prim description is abc,123
then do list desclist = llCSV2List(llGetObjectDesc());
string somestring = llList2String(desclist,0); // returns abc
integer channel = llList2Integer(desclist,1); // returns 123 as a integer