perfect:{(x>2)&x=+/-1_{d:&~x!'!1+_sqrt x;d,_ x%|d}x}
   perfect 33550336
1

   a@&perfect'a:!10000
6 28 496 8128

   m:3 10#!30
(0 1 2 3 4 5 6 7 8 9
 10 11 12 13 14 15 16 17 18 19
 20 21 22 23 24 25 26 27 28 29)

   perfect'/: m
(0 0 0 0 0 0 1 0 0 0
 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 1 0)