Permalink Submitted by Anonymous on December 27, 2014

Nice puzzle, and a nice homage to Ramanujan and the taxi number that brought GH Hardy to see him in hospital. Fujiwara (1729) showed 1729 is one of four positive integers (with the others being 81, 1458, and the trivial case 1) which, when its digits are added together, produces a sum which, when multiplied by its reversal, yields the original number.

## Taxi number

Nice puzzle, and a nice homage to Ramanujan and the taxi number that brought GH Hardy to see him in hospital. Fujiwara (1729) showed 1729 is one of four positive integers (with the others being 81, 1458, and the trivial case 1) which, when its digits are added together, produces a sum which, when multiplied by its reversal, yields the original number.