Given an integer `x`, return `true` if `x` is a palindrome, and `false` otherwise. An integer is a palindrome when it reads the same backward as forward.
**Example 1:**
```
Input: x = 121
Output: true
```
**Example 2:**
```
Input: x = -121
Output: false
```
**Example 3:**
```
Input: x = 10
Output: false
```