Tomorrow, April 26, is notable for two reasons.

First, it’s my birthday. I’ll be 39. Again. That’s my story and I’m sticking to it.

Second, it’s 100 years since the death of Srinivasa Ramanujan, one of the greatest mathematical geniuses of all time.

Ramanujan was born in India in 1887. He got a basic high school education, but was expelled from college because he ignored everything except mathematics. Eventually, he ended up at Cambridge University in England.

His mentor at Cambridge was G.H. Hardy, a famous number theorist. Hardy wrote about visiting Ramanujan in the hospital in 1917:

“I had ridden in taxi-cab No. 1729, and said that the number seemed to me a rather dull one. ‘No,’ he replied, ‘it is a very interesting number: It is the smallest number expressible as a sum of two cubes in two different ways.'”

Say what?!

Ramanujan didn’t need to think about it. He could just see it. Hardy, in amazement, went back to his office and worked it out on paper. Ramanujan was right.

That kind of insight was actually a point of contention between Hardy and Ramanujan. In mathematics, it’s not enough just to know something: you must be able to prove it. It was so easy for Ramanujan to see things that he wasn’t accustomed to proving them. He could prove them, and he did, but only after Hardy nagged him to do it.

Tragically, Ramanujan died at 32 of a liver infection for which we now have a cure.

Since he mostly worked on number theory, his discoveries are too esoteric for most people to appreciate. I studied them for my mathematics degree, but even I only understand one of them (his work on continued fractions) really well. Number theory is widely used today in computer science, especially in computer security.

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