Completely meaningless statistic.

Bitcoin ASIC miners can't even compute a floating point operation so they are not at all comparable to a supercomputer that can be used for many things.

Comparing specialized bitcoin hardware to supercomputers simply can't be done. The bitcoin network is faster at performing SHA256 hashes, but thats it.

Assuming the supercomputers also are quite capable of integer arithmetic, it would be interesting to have an estimate of the mining hashpower such machines have.

Usually they aren't very good at integer math. Most calculations use floating point. Unfortunately, most of the important constants in science are not integers (pi, e, phi, etc) and rarely are the things you want to measure integer length.