A:~ au$ perl -MDevel::Peek -e 'Dump 3'
SV = IV(0x100827190) at 0x100827198
  REFCNT = 1
  FLAGS = (IOK,READONLY,pIOK)
  IV = 3
A:~ au$ perl -MDevel::Peek -e 'Dump "3"'
SV = PV(0x100801258) at 0x1008271b0
  REFCNT = 1
  FLAGS = (POK,READONLY,pPOK)
  PV = 0x100207f60 "3"\0
  CUR = 1
  LEN = 16