That answer depends upon the 5 cards you discarded.
Assuming you did NOT discard ANY royal flush card (TJQKA), then the
chance of drawing a royal flush is 47 choose 5 divided by 4,
or once every 383,484.75 hands. If you are playing a normal JOB type
game then it is quite common to have discarded a single T and now the
odds would be 1 in 511,313 hands.
For wild card games, you often discard 1 or more unsuited royal cards and
this of course greatly reduces your redraw RF opportunities.
G'luck
Gamb00lin F00l(s)
ยทยทยท
There are 2,598,960 possible in a 52 card deck, 4 of which are Royals,
so the answer is 649,740 to one.
and what would be the odds when tossing a complete firsthand only to receive
a royal on the re-draw?