Number Problems

1. Reverse an integer without converting it to a string.
2. Check whether a number is a palindrome.
3. Count the digits in a number.
4. Find the sum of a number’s digits.
5. Check whether a number is prime.
6. Print the first n Fibonacci numbers.
7. Find the factorial of a number.
8. Find the greatest common divisor of two numbers.
9. Find all Armstrong numbers in a range.
10. Find the second-largest distinct number in a list.