Texas Hold'em Jackpot

I came across a Texas Holdem game where a Jackpot payout was made if a player has a Royal Flush on either Flop, Turn or River (paying out 100%, 20% and 10%). The "catch" is that the player must use their 2 hole cards in forming RF.
My question is, what are the odds of hitting RF on Turn or River while holding 2 RF cards.
Many thanks!

The odds of being dealt a Royal Flush in a 5-card poker game like Mississippi Stud are approximately 1 in 649,740.

The jack pot should be 10 times easier than the above number. So,

1 in 64,974.