Retrieve a message in a deck of cards!

There are 52! unique ways to put 52 playing cards in order. By establishing a mathematical correspondence between an order of letters and the order of cards, we can hide a message in the deck of cards by simply putting them in the correct order. Read a full explanation, play with the encoding demo, or the decoding demo below.

I used the free javascript BigInt library to do large-number calculations.

Comments welcome at

Source cards: (click a card here to move it into the next slot of the pattern)
Decoded number:
Decoded message: