Srinivasa Ramanujan Iyengar Tamil: ஸ்ரீனிவாச ராமானுஜன் (December 22, 1887 – April 26, 1920) was an Indian mathematician. He is considered to be one of the most talented mathematicians in recent history. He had no formal training in mathematics. However, he still made large contributions to number theory, infinite series and continued fractions.

He was mentored by G. H. Hardy in the early 1910s. After getting his degree at Cambridge, Ramanujan did his own work. Some of the identities were found in his “lost notebook”. When the notebook was discovered, mathematicians proved almost all of Ramanujan’s work. His discoveries have led to many advancements in mathematics. His formulas are now being used in crystallography and string theory.

He was an Indian mathematician and autodidact who, with almost no formal training in pure mathematics, made extraordinary contributions to mathematical analysis, number theory, infinite series, and continued fractions. Ramanujan initially developed his own mathematical research in isolation, which was quickly recognized by Indian mathematicians. When his skills became apparent to the wider mathematical community, centered in Europe at the time, he began a famous partnership with the English mathematician G. H. Hardy. He rediscovered previously known theorems in addition to producing new work. Ramanujan was said to be a natural genius, in the same league as mathematicians such as Euler and Gauss.

During his short life, Ramanujan independently compiled nearly 3900 results (mostly identities and equations). Nearly all his claims have now been proven correct, although a small number of these results were actually false and some were already known. 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. The Ramanujan Journal, an international publication, was launched to publish work in all areas of mathematics influenced by his work.