recentf-save-file-modes

recentf-save-file-modes is a variable defined in `recentf.el'.
Its value is

384

Documentation:
Mode bits of recentf save file, as an integer, or nil.
If non-nil, after writing `recentf-save-file', set its mode bits to
this value. By default give R/W access only to the user who owns that
file. See also the function `set-file-modes'.

You can customize this variable.