[C++] Simple Solution
Code
# Code
```cpp []
class Solution {
public:
    int smallestNumber(int n) {
        int cur = 1;
        int mult = 2;
        while(cur <= n) {
            if(cur >= n) return cur;
            cur += mult;
            mult *= 2;
        }
        return cur;
    }
};
```
['C++']