You might be able to find some numbers that almost work.
25 would become 52, which is close to 25(2) = 50
102 would become 210, which is close to 102(2) = 204
What is my number? I’ll give you a hint: you are unlikely to solve for the answer by casually guessing it. But a genius might be able to. Legendary mathematician Freeman Dyson apparently heard the problem and instantly replied with the number of digits in the answer.