[anthonyrstevens]

>> Number theory had no practical applications until the development of public-key cryptography

This is so wrong I don't even know where to begin. Modular arithmetic, numerical integration, pseudorandom number generation, error-correcting codes, predicting planetary orbits (!), etc.

[Eufrat]

At the risk of asserting the claim was obviously a bit facetious, number theory had the reputation of having very little practical applications and I don’t mean that silly quote by G. H. Hardy.

A lot of applications just required a lot more computing power to be practical. This all starts to happen around the same time (unsurprisingly) and if you’re going to make hay that Reed-Solomon coding was invented in 1960, I think it’s worth pointing the first big use of was on Voyager because the computing power was finally able to make these work. It’s not like people hadn’t started to notice some of this decades earlier.