@extra-number/proper-divisors (npm): Gives a list of numbers that n is divisible by, except itself (see proper divisors).
Keywords: extra|number|proper|divisors|properDivisors|aliquot-sum|arithmetic-mean|binomial|ceil|ceil-div|compare|constrain|cubic-mean|degrees|factorial|floor|floor-div|gcd|geometric-mean|harmonic-mean|is|is-pow|is-prime