It is thought that Hurley's winning lottery numbers - 4, 8, 15, 16, 23 and 42 - came to him, indirectly, from the island itself. The transmitter on the island has been broadcasting them since World War II, according to Martha Toomey, whose husband passed them to the man who passed them to Hurley. They are also engraved on the mysterious hatch in the jungle.
Hurley researched where the numbers came from. It turns out, the patient at the insane asylum who mumbled the numbers that Hurley played also befell bad luck as did people before them who used the numbers. They were cursed. Sure enough Hurley was cursed too.
48 People started on the island. 4 are now gone. The last episode hinted that there will be one more. So, there are now 44 survivors on the island right now, with a possible 2 more going soon, or not. You never know on this show, what is real and what isnt.
The number 815 also recurs through the story - as Flight 815, as two of Hurley's lottery numbers (8 and 15), as Sayid's room number at his Sydney hotel, as the model of the photocopier (the C815) Charlie sells in a flashback, in Locke's encounter with his mother (he points to aisles 8 and 15), as the date of Kate and Tom's time-capsule tape (August 15, or 8/15) and as the number of the bank deposit box Kate is trying to break into.