There is a certain species of the cicada insect that has a life cycle of 17 years. Seventeen, of course, is a prime number. But why does an individual of this species remain in the larvae phase for exactly 17 years, before a whole mass of them burst into adulthood, ready to mate? One theory is that a predator once lurked the earth that had a shorter life span. The adults of this predator would thus perish before the next group of cicadas was ready to lay eggs. Any other mathematical equation and every few batches of cicadas would end up as a massive cyclical feast for the predator. So, the prime number of 17 was nothing but an in-built survival mechanism.

This and other equally fascinating nuggets form the subject matter of Weird Maths (HarperCollins). But possibly the weirdest, or rather most astonishing, mathematical fact about the book is the age of its co-author Agnijo Banerjee, who wrote it in collaboration with David Darling, his tutor for five years. Banerjee is 17. He has an IQ of 162. That’s equal to Albert Einstein’s, as certified by Mensa. He was acing higher maths exams in his first year of secondary school in Dundee — having moved there from Kolkata as an infant — while also breezing through international maths Olympiads. And he’s now readying to join Cambridge to study the subject further, after completing Weirder Maths, a sequel to the first book. Clearly, he is a genius, without stretching the word one bit.