Srinivasa Ramanujan (1887–1920) was an Indian mathematician whose extraordinary contributions to number theory, mathematical analysis, and infinite series left a lasting impact on the field of mathematics. Ramanujan’s work was particularly notable for its originality and depth, and he made significant discoveries independently, often with little formal training in advanced mathematics.

Key points about Srinivasa Ramanujan’s life and mathematical contributions include:

1. Early Life: Ramanujan was born on December 22, 1887, in Erode, Madras Presidency (now in Tamil Nadu, India). He showed an early aptitude for mathematics and independently discovered many results on his own.
2. Self-Taught Mathematician: Ramanujan largely taught himself mathematics through books and his own insights. His early notebooks contain a wealth of mathematical results and conjectures.
3. Entry to Cambridge: Despite facing financial difficulties and challenges, Ramanujan’s work came to the attention of British mathematicians, including G. H. Hardy. With Hardy’s support, Ramanujan traveled to Cambridge in 1914 to collaborate and further develop his mathematical ideas.
4. Contributions to Number Theory: Ramanujan made numerous contributions to number theory, including discoveries related to partitions of integers, modular forms, and mock theta functions. His work on highly composite numbers and the partition function remains influential.
5. Ramanujan-Hardy Number: The number 1729 is known as the “Ramanujan-Hardy number” or the “taxicab number.” It is famous for an anecdote involving a visit by Hardy to Ramanujan in the hospital. Hardy mentioned that he arrived in a taxi with a rather uninteresting number, 1729, only for Ramanujan to respond that 1729 was actually a very interesting number—it is the smallest positive integer that can be expressed as the sum of two cubes in two different ways: 1729=13+123=93+1031729=13+123=93+103.
6. Illness and Return to India: Ramanujan’s health deteriorated during his time in England, possibly due to malnutrition and other factors. He returned to India in 1919 but succumbed to illness and passed away on April 26, 1920, at the age of 32.
7. Legacy: Srinivasa Ramanujan’s legacy continues to influence mathematics. His notebooks, containing a wealth of unpublished results, have been studied and explored by mathematicians. The Ramanujan-Hardy number, as well as various formulas and theorems, bear his name. The Ramanujan Prize and Ramanujan Day are among the commemorations of his contributions to mathematics.

Ramanujan’s life and work have been the subject of books, documentaries, and films, and he is widely regarded as one of the most remarkable mathematicians of the 20th century.