Lemaire, a 27-year-old doctoral student in artificial intelligence from Reims, near Paris, was presented with the randomly-picked 200-digit number by a computer, which displayed the figure over 17 lines on the screen.
Lemaire then took just over a minute to identify two quadrillion, 397 trillion, 207 billion, 667 million, 966 thousand, 701 as the 13th root.
In other words, the number multiplied by itself 13 times produces the 200 digit number originally generated by the computer.
"The first digit is very easy, the last digit is very easy, but the inside numbers are extremely difficult," the mental gymnast, who says he doesn't consider himself a nerd or a geek, said.
Lemaire, who sports a beard and glasses under thickly-matted eyebrows and a furrowed brow, previously performed the feat in 77 seconds and has been working at the 13th root problem for years, repeatedly eroding his best time.
"I use an artificial intelligence system which I use on my own brain instead of on a computer," he explained, matter-of-factly.
"Personally, I believe most people can do it but I have also a high-speed mind. My brain works sometimes very, very fast."
