Today I wish to discourse about a favorite number. To stretch a favorite RIU phrase, I'm "about to expound".
The Ramanujan number is 1729. A mathematician called Srinivasa Ramanujan spoke of it in the nearest thing mathematicians have to stories that make it into general usage. His number is the sum of two distinct sets of cubes, integers raised to the third power.
1 cubed is 1, ever and always.
729 is nine cubed.
Ten cubed is (wait for it) a thousand.
Twelve cubed is 1728.
So 1729 is 9E3 + 10E3 and also 12E3 + 1E3.
This number has a Wiki entry. Follow the link on "sphenic numbers". These are multiples of three distinct primes. I encountered one such when I was a kid ... I laboriously factored 1001 once on a long boring car trip. It is 7 x 11 x 13.
https://en.wikipedia.org/wiki/1729_(number)