Great Ramanujam found 1729 as a magic number, what was the magic about it?

Question

1729 is also known as hardy-ramanujan number. While they were going in a taxi, Mr. Hardy told Ramnujan that what a boring number is this(referring to the taxi number 1729) then Ramanujan told him how interesting is this number!

Now the question is what was so interesting in it.

Answer 1

It is the smallest number expressible as the sum of two cubes in two different ways.
The two different ways are:
1729 = 13 + 123 = 93 + 103