If you read the firstpost of the bitcrack there is a 32bitcoin reward puzzle ( $1 900 000)

The 2^63 has been found, but the 2^65 is still available.

https://privatekeys.pw/puzzles/bitcoin-puzzle-tx

puzzle 65 = 0.65 bitcoin

The private keys were made by taking a random number and then masking it to the desired bit length:

#1 = 256 bit random number bit wise ANDed with (21 - 1)
#2 = 256 bit random number bit wise ANDed with (22 - 1)
#3 = 256 bit random number bit wise ANDed with (23 - 1)
...
#60 = 256 bit random number bit wise ANDed with (260 - 1)
#61 = 256 bit random number bit wise ANDed with (261 - 1)
#65 = 256 bit random number bit wise ANDed with (265 - 1)
#70 = 256 bit random number bit wise ANDed with (270 - 1)
#75 = 256 bit random number bit wise ANDed with (275 - 1)
...
#160 = 256 bit random number bit wise ANDed with (2160 - 1)