1729 is called Ramanujan’s number. This number became famous through the conversation bwteen two great mathematicians – Srinivas Ramanujan and Godfrey Harold Hardy. English mathematician G.H. Harold narrated
” I remember once going to see him when he was ill at Putney. I had ridden in taxi cab number 1729 and remarked that the number seemed to me rather a dull one, and that I hoped it was not an unfavorable omen. “No,” he replied, “It is a very interesting number; it is the smallest number expressible as the sum of two cubes in two different ways.”
The number 1729 can be expressed as sum of cube of 1 & cube of 12 and cuber of 9 & cuber of 10.
1729 = (1)3 + (12)3 = (9)3 + (10)3