a_d_b.p6

# https://rosettacode.org/wiki/Abundant,_deficient_and_perfect_number_classifications#Perl_6

sub propdivsum (\x) {
   [+] flat(x > 1, gather for 2 .. x.sqrt.floor -> \d {
      my \y = x div d;
      if y * d == x { take d; take y unless y == d }
   })
}

say bag map { propdivsum($) <=> $_}, 1..20000


# produces error:
#
# Use of uninitialized value of type Any in numeric context
#   in sub propdivsum at a_d_p-nums.p6 line 4
# No such method 'sqrt' for invocant of type 'Any'
#   in sub propdivsum at a_d_p-nums.p6 line 5
#   in block <unit> at a_d_p-nums.p6 line 11