$ include "seed7_05.s7i";
  include "rational.s7i";

const func boolean: isPerfect (in integer: candidate) is func
  result
    var boolean: isPerfect is FALSE;
  local
    var integer: divisor is 0;
    var rational: sum is rational.value;
  begin
    sum := 1 / candidate;
    for divisor range 2 to sqrt(candidate) do
      if candidate mod divisor = 0 then
        sum +:= 1 / divisor + 1 / (candidate div divisor);
      end if;
    end for;
    isPerfect := sum = rat(1);
  end func;

const proc: main is func
  local
    var integer: candidate is 0;
  begin
    for candidate range 2 to 2 ** 19 - 1 do
      if isPerfect(candidate) then
        writeln(candidate <& " is perfect");
      end if;
    end for;
  end func;