What is the number found by Ramanujan?

The number found by Ramanujan is 1729, also known as the Hardy–Ramanujan number. It is famous for being the smallest nontrivial taxicab number, which means it is the smallest number that can be expressed as the sum of two positive cubes in two different ways. Specifically, 1729 = 1³ + 12³ and 1729 = 9³ + 10³.