Question

What is amazing about the square of 111, 111, 111?​

Answer 1

The square of 111,111,111 is 12,345,678,987,654,321. What's amazing about it is that if you read the digits from left to right, then it's a palindrome. If you read the digits from right to left, it's also a palindrome. This property makes it a doubly-palindromic number, which is quite rare and interesting.