[FreeRadical]

1729 was also Ramanujan’s taxi number

https://mathworld.wolfram.com/Hardy-RamanujanNumber.html

[dhosek]

This is how I remember that 1728 = 12³. I remember getting puzzled looks from classmates in my elliptic curves class first when I was able to provide 12³ without a moment's delay and then again when I explained why I knew that.

[paulpauper]

it's because 12^3 differs from 1729 by just 1, making the error very small when using series