sounds as if you're a bit confused about the view you're looking at.
It's only 1 address with 500k that has received small bits of coins, more then likely mining rewards on x11 payed out to the wallet.
the balance is re-printed in this blockchain for each input they have an output showing you the current balance.
There is technically 21.8 million pre-mined coins with about 12,500,000 that is unaccounted for and still idling in the hands of the dev.
see the transparent discussion here for further information about the 21.8million pre-mined coins :
https://bitcointalk.org/index.php?topic=829975.msg9273790#msg9273790
