The world's fastest human calculator, Alexis Lemaire recently broke his own record for working out the 13th root of a random 200-digital number from a possible 393 trillion answers. He did it in 70.2 seconds.

The 'Mathlete' produced the answer of 2,407,899,893,032,210 in 70.2 seconds, beating his previous record of 72.4 seconds, at London's Science Museum. So if the world is ever about to be overran by evil mathematicians he's your man.