- Difficulty: Medium
- Tags: LeetCode, Medium, Math, Number Theory, leetcode-866, O(n^(1/2) * (logn + n^(1/2))), O(logn)
Problem
Given an integer n, return the smallest prime palindrome greater than or equal to n
.
An integer is prime if it has exactly two divisors: 1
and itself. Note that 1
is not a prime number.
- For example,
2
,3
,5
,7
,11
, and13
are all primes.
An integer is a palindrome if it reads the same from left to right as it does from right to left.
- For example,
101
and12321
are palindromes.
The test cases are generated so that the answer always exists and is in the range [2, 2 * 108]
.
Example 1:
Input: n = 6 Output: 7
Example 2:
Input: n = 8 Output: 11
Example 3:
Input: n = 13 Output: 101
Constraints:
1 <= n <= 108