**1729 is**smallest

**taxicab**number , i.e., the smallest number representable in two ways as a sum of cubes. It is given by

**1729 = 12³ + 1³**

**1729 = 10³ + 9³**

**The number derives its name from the following story:**

G. H. Hardy told about Ramanujan. I remember once going to see him when he was ill . I had ridden in taxi cab number 1729 and remarked that the number seemed to me rather 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."

**1729 is the second taxicab number**(the first is 2= 1^3 + 1^3). The number was also found in one of Ramanujan's notebooks dated years before the incident.

**"Every positive integer is one of Ramanujan's personal friends."—**J.E. Littlewood, on hearing of the taxicab incident

**More details are available on the attached link**.

Source(s):

http://en.wikipedia.org/wiki/1729_(number)