13th root but what's the point?

Is this guy human or what? I could hardly calculate the square root of a 4 digit number mentally and this French guy could do a 13th root of a two hundred digit number all in his head!!!! And all just slightly more than a minute!!! Impossible or what !???

Very impressive, but what actually is the point? Learning a language has an obvious benefit, as does the ability to complete basic mental calculations, but given the time and training involved in this feat, one has to wonder if there aren't more productive means of employing intelligence.
- Jenny, London