Once Ramanujan, who was in London, was sick.

Hardy came to visit him in a Taxi.

This was the conversation

That’s a very dull number

From then on,

number 1729 is known as Hardy-Ramanujan Numbers

1729 can be expressed as

1729 = 1 + 1728 = 1
^{
3
}
+ 12
^{
3
}

Or

1729 = 729 + 1000 = 9
^{
3
}
+ 10
^{
3
}

Thus,

1729 is the smallest number that can be represented as sum of two cubes in two different ways