The number you're thinking of is 52! (52 factorial) and how long it would take for 52! seconds to pass by.
Vsauce has a great video on this, and might be where that example was taken from.
https://www.youtube.com/watch?v=ObiqJzfyACM
That example starts 16 minutes into the video:
https://www.youtube.com/watch?v=ObiqJzfyACM&t=964s
But it's worth watching the whole thing.