Special number

   What is special about this number 1729 ─?

Answer:     This is the only known number that is a sum of two cubes n two different ways.

Example: 10ᶾ + 9ᶾ = 1729, 12ᶾ + 1ᶾ = 1729

          This is popularly known as Ramanujam’s number. There is an interesting story about it. The story goes this way. When Ramanujam was sick in the hospital, Prof. Hardy, his tutor paid him a visit. Prof. Hardy told Ramanujam that he rode a taxicab to the hospital, with a very unlucky number.

         When Ramanjam enquired what the number was, Prof. Hardy replied: 1729.

          Ramanujam’s face lit up with a smile and he said that it was not an unlucky number at all, but a very interesting number, the only number that can be represented as the sum of two cubes in two different ways!