Currently, the computing power on the Bitcoin network is 1.35 zetta flops (sextillion FLoating-point Operations Per Second). That is 5,000 times greater than the power of all of the worlds fastest 500 supercomputers combined.
Wow. Is this accurate? I don't know much about flops and computer power, but I was under the impression the hashrate was about 135 petaflops. Either way, this is quite a massive achievement!
Hashing doesn't actually involve any floating-point operation. Measuring hashing power in FLOPS just doesn't make sense.
That said, the Bitcoin network is very likely to be the biggest distributed computing project ever created...