# The fascinating story behind Hardy-Ramanujan number

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Srinivasa Ramanujan, the man who knew infinity, was one of India’s greatest mathematicians.

## Early life

Ramanujan was born on 22 December 1887 in Erode, a village 400 km southwest of Madras. He made significant contributions to the analytical theory of numbers and also worked extensively on elliptic functions and infinite series.

Ramanujan’s father worked as a clerk in a cloth merchant’s shop in Kumbakonam. At the age of five, he joined the primary school in Kumbakonam. He joined the Town High School in Kumbakonam in January 1898. He was awarded the K. Ranganatha Rao prize for mathematics by the school headmaster in the year 1904.

He studied at Pachaiyappa’s college. He was a researcher at the University of Madras. Ramanujan was the first Indian to be elected a Fellow of Trinity College, Cambridge.

Those with great interest in Mathematics worldwide, will also remember him for the Hardy-Ramanujan number!

## 1729- The Hardy-Ramanujan Number

The ‘anecdote’ behind the Hardy-Ramanujan number is mentioned in Ramanujan’s biography ‘The Man Who Knew Infinity’ by Robert Knaigel.

British Mathematician G.H. Hardy visited Ramanujan while he was in the hospital. Hardy told Ramanujan that he came in a taxi numbered ‘1729’, which he felt was a dull number and feared of being a bad omen. Ramanujan immediately corrected Hardy. He told Hardy that ‘1729’ was not an ordinary number! It is the smallest number which can be expressed as the sum of two different cubes in two different ways. Thus the Hardy-Ramanujan number came into existence.

‘1729’ is the sum of the cubes of 10 and 9, and also the sum of the cubes of 12 and 1.

While the Hardy-Ramanujan number is just one among the many fascinating discoveries of the great mathematician, it is definitely an interesting one!

## Recognition

Ramanujan featured on Nature’s “Calendar of Scientific Pioneers.” There are several stamps issued by the government of India in honor of the great mathematician. His home state Tamil Nadu celebrates his birthday as ‘State IT Day’.

His birthday is observed as Ramanujan Day by the Government Arts College, Kumbakonam and IIT Madras. The ICTP in association with the International Mathematical Union gives prizes in Ramanujan’s name to young mathematicians from developing countries. For outstanding contributions in the area of Mathematics, SASTRA Ramanujan Prize(\$10,000) is given annually to mathematicians below the age of 32.

Based on the UGC recommendations, the Srinivasa Ramanujan Center has been established by the SASTRA university. The center has a museum dedicated to the legendary mathematician. SASTRA university has also renovated Ramanujan’s house in Kumbakonam.

In 2011, on the 125th birth anniversary of Srinivasa Ramanujan, the Indian government declared that 22nd December will be celebrated every year as ‘National Mathematics Day’. Prime Minister Manmohan Singh had also declared 2012 as National Mathematics Year.

Spread over 25 acres, the Ramanujan IT City is a special economic zone built in Chennai in 2011.

Even though Srinivasa Ramanujan died at a young age of 32, he continues to live through his works. He made our country proud with his brilliance and passion for the subject of mathematics.