IF bittrex exchange will not tolerate with the number of coins exceeding the 4.5 Millions limit, then the solution is forking the coin by making the last minable block become
BLOCK#10120.
Otherwise, everything will be fine.
This is the link of the excel sheet if anyone wants to check it and revise the calculations:
http://www.mediafire.com/download/8svdlr3tds8bk6t/DarkKushCoin+DANK+-+Calculations.xlsxEDIT: I've sent Mr. Richie of Bittrex exchange a message to check this out.