C:\test>perl -MDevel::Peek -E"my $x = '12345'; Dump $x; $x *=1; Dump $x"
SV = PV(0x6cf50) at 0xc74e8
  REFCNT = 1
  FLAGS = (PADMY,POK,pPOK)
  PV = 0x67758 "12345"\0
  CUR = 5
  LEN = 8

SV = PVIV(0xaf018) at 0xc74e8
  REFCNT = 1
  FLAGS = (PADMY,IOK,pIOK)
  IV = 12345
  PV = 0x67758 "12345"\0
  CUR = 5
  LEN = 8