Srinivasa Ramanujan (22 December 1887 -26 April 1920), a prodigy from Tamil Nadu, was a self-taught mathematician with incredible intuition. With almost no formal training in pure mathematics, he had made groundbreaking contributions to mathematical analysis, number theory, infinite series and continued fractions.
Ramanujan independently wrote down nearly 3900 results during his short lifetime, and most of his claims have now been proven. He stated results that were both original and highly unconventional, such as the Ramanujan prime and the Ramanujan theta function, and these have inspired a vast amount of further research. Indeed, some of his major discoveries have recently found applications in crystallography and string theory, to name just two fields. He made substantial contributions to the analytical theory of numbers and worked on elliptic functions, continued fractions, and infinite series.
A common anecdote about Ramanujan relates to the number 1729, which was mentioned to be uninteresting. On the spot he is said to have stated that it was actually a very interesting number mathematically, being the smallest number representable in two different ways as a sum of two cubes:
1729=13 +123 =93 +103
Generalizations of this idea have spawned the notion of "taxicab numbers".
Coincidentally, 1729 is also product of 3 prime numbers
The largest known similar number is
885623890831=75113 +77303=87593 +59783 =3943x14737x15241
Some of his most outstanding contributions were his formula for p (n), the number of 'partitions' of 'n' - the number of partitions of n, his work on the tau function (the Ramanujan conjecture), and mock theta functions. As a tribute to Ramanujan and to commemorate his birthday, December 22 is celebrated as 'National Mathematics Day.' Ramanujan's natural genius and his work in mathematics was original and far beyond his time. It will continue to inspire generations of mathematicians to come. For more on Ramanujan, see https://en.wikipedia.org/wiki/Srinivasa_Ramanujan.