Rashad is trying to sleep

Rashad has problems with sleeping. Sleeping is most important for scientists and programmers, because their brains work a lot. Huseyn told Rashad a very interesting technique that will help him to sleep: at night Rashad must find the $k$-th interesting number. An interesting number is a number where the last digits of its square are identical to the number itself. For example, $376$ is an interesting number, because 376 \cdot 376 = 141376. The last digits of $141376$ are $376$, and they are identical to the number. While Rashad was trying to find the $k$-th interesting number, he went to his sweet dream. Can you find the $k$-th interesting number?