100030001

This number is a prime.

The smallest square-congruent prime. [Loungrides]

The smallest and only known prime which starts and ends with the digit 1, such that a prime p is centered between p zeros on each side. Can you find another example? [Sariyar]

100030001 remains prime after deleting a zero simultaneously in each wing, i.e., 100030001, 1003001, 10301, and 131. Finally, 1+3+1 is also prime. [Marcel]