Odd Prime

Prime number seems to be trending topic for programming contest. As such, Piyash, being an aspiring competitive programmer, started learning about theories and algorithms related to prime numbers. A prime number is a positive integer $p \gt 1$ that has no positive integer divisors other than $1$ and $p$ itself. Piyash read somewhere that all prime numbers except $2$ are odd.


This is a companion discussion topic for the original entry at https://toph.co/p/odd-prime