You misinterpreted the quote.
The number of atoms on the surface of earth(1) is 1.26 x 1034 and the number of atoms on earth is 1.33 x 1050 (does not concern us here).
The total number of IPV6 that we can assign is: 3.4 x 1038.
3.4 x 1038 > 1.26 x 1034.
The following is true and here is the full quote for you:
BUT, there are 6-billion people on the planet, so if everyone was
assigned just one IP address, we’d run out and leave 1/3rd of the
world without IP addresses. So they invented IPV6, a 128-bit value,
which is 16-bytes long. Since they had to identify this to distinguish
it from 4-byte values, the 1st byte has a 1-byte value that was never
used in the 1st byte of the original 32-bit addresses. So that leaves
2120 possible IP addresses using IPV6. How big is that? Well, several
web sites say there are 1.33 x 1050 atoms in the earth. That’s way
bigger than 2120. But to make it come closer, I computed the number
of atoms on the surface of the earth. That turns out to be 1.26 x
1034 atoms. 2120 is 1.33 x 1036, which is still bigger by 105 times.
So we could assign an IPV6 address to EVERY ATOM ON THE SURFACE OF THE
EARTH, and still have enough addresses left to do another 100+ earths.
It isn’t remotely likely that we’ll run out of IPV6 addresses at any
time in the future.
(1) The number of atoms on the surface = 4πr2 x (1/2a)2. Planet's radius = 6378km, mean atomic radius of the common stuff averages about 100pm. Total= 1.27*1034 . calculated by paul (see the comments).