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”
— G. H. Hardy
Euler Function on the Complex Plane
Yep, it is ALSO the first absolute Euler pseudoprime. Unique. Sui Generis.
Just like The Man Who Knew Infinity:
Srinivasa Ramanujan: Sui Generis