10^53 kg / 2^128 = 10^14 kg per address, though I have no idea what fraction of the universe is sand.
In practice, the number of allocations is much smaller because IPv6 is effectively a 64 bit address space, with the second half reserved for edge networks.
https://en.wikipedia.org/wiki/Observable_universe estimates 10^53 kg in the observable universe.
10^53 kg / 2^128 = 10^14 kg per address, though I have no idea what fraction of the universe is sand.
In practice, the number of allocations is much smaller because IPv6 is effectively a 64 bit address space, with the second half reserved for edge networks.