The functions of a factorisation, the p-adic valuation, the n-th prime and the prime-counting
function, for the compilers, by the routines the interpreter uses: exact at a whole argument, and
NaN at any other, where none of them has a value, and where the interpreter leaves one as
written, a number too large to factorise or a prime too far to build towards. The gcd and the lcm
likewise, though evaluation has them at a rational too.
https://github.com/asc-community/AngouriMath/issues/2195