## Powerful digit counts

### Problem 63

Published on Friday, 13th February 2004, 06:00 pm; Solved by 22796The 5-digit number, 16807=7^{5}, is also a fifth power. Similarly, the 9-digit number, 134217728=8^{9}, is a ninth power.

How many *n*-digit positive integers exist which are also an *n*th power?