The math is 2 to the power of 64 multiplied by 512 bytes (per block) for a total of 8 ZB (or 9,444,732,965,739,290,427,392 bytes).
The maximum volume size could be 151,115,727,451,828,646,838,272 bytes (2 to the power of 64 times 8196 - a block size of 8 KB) or 147 ZB.