Tags

Leo came to me one day, probably about 2 years ago, and told me that 25 is his favorite number.

“Because you can put the 2 next to it, or above it!”, said he, rationally.

“Hunh?”, said I, confusedly.

“See!”, said he, demonstratively, and he wrote:

$25=5^2$

“Wow! Cool!”, exclaimed I exclamatorally!

(I obviously made the details of this conversation up as it was 2 years or so ago!)

I actually had to write a program to prove to myself that there is only one other number, less than 10,000 that has this property; specifically, that you can take one of the digits out, raise the remaining digits combined to the extracted digit’s power, and get the original number back.

I leave the solution to the reader! 🙂

By the way, I was ready to publish, but figured that this was so obvious (in retrospect) that it must have been figured out before. Of course it has; they are called Friedman numbers.