I Put My Prime Down, Flip It and Reverse It

A prime number is a number whose only proper (non-self) divisor is 1 (example 13).

An emirp (prime spelled backwards) is a non-palindromic prime which, when its digits are reversed, makes another prime. E.g. 13 is a prime, and so is 31. Both are therefore emirps.

A bemirp is a prime which is an emirp (makes another prime with its digits reversed), but additionally, makes another prime when flipped upside down (see note). The upside-down version is also an emirp, which makes a group of 4 primes. Bemirps consist only of digits 0, 1, 6, 8, and 9.

To illustrate: 11061811, reversed = 11816011, upside-down = 11091811, upside-down reversed = 11819011. All four are primes.

Create a function that takes a number and returns "B" if it’s a bemirp, "E" if it's a (non-bemirp) emirp, "P" if it's a (non-emirp) prime, or "C" (composite / non-prime).

Examples

bemirp(101) ➞ "P"

bemirp(1011) ➞ "C"

bemirp(1069) ➞ "E"

bemirp(1061) ➞ "B"

Notes

6 upside-down is 9 and vice-versa. 0, 1, and 8 are unchanged when flipped. The remaining five digits are unflippable.