According to Seth Palanksy via Twitter, the final number of entrants for Day 1a was 4,722, Quite the turnout and with Day 1b registration open until 11:45 pm and 7,707 entrants it's completely possible that we'll top the 8,000 entrant mark. To put this into perspective, this is now the 2nd largest live poker tournament in history:
2006 WSOP Main Event - 8,773 entrants
2014 WSOP Millionaire Maker - 7,707 and growing
2010 WSOP Main Event - 7,319 entrants
2011 WSOP Main Event - 6,865 entrants
2008 WSOP Main Event - 6,844 entrants
The big difference, however, is this event seats all the players in one day while the WSOP Main Event has always had 3-4 starting days. An impressive feat to say the least.