proc digitalRoot n . x persistence .
   numberString$ = n
   currentPersist = 0
   while len numberString$ > 1
      for i = 1 to len numberString$
         sum += number substr numberString$ i 1
      .
      numberString$ = sum
      currentPersist += 1
      sum = 0
   .
   x = number numberString$
   persistence = currentPersist
.
numbers[] = [ 627615 39390 588225 393900588225 ]
for i in numbers[]
   digitalRoot i x persistence
   print i
   print "Additive persistence: " & persistence
   print "Digital root: " & x
.