This mantra to be chanted in hanuman temple for 21 days without break, while doing pradakshana.
Thursdays or Saturdays for karaya siddhi..
later you need to give prashad to devotees and do poor feeding (annad danam)
its always the odd number .. 9, 11, 21, 27, 41 (one mandala) or 108
(3) (9)...