I have set up several profiles including phone numbers.
One of the profiles is used on the user account screen, and the numbers are blank in the view screen (but the labels are still there). However the numbers are displayed on the edit screen.
Another profile is used for search/profile listings and the phone number is supposed to be displayed in the selector table but is blank, as well as being blank in the details view.
I reproduced this on the sandbox using a profile with a first name and one number here: http://demo.openngo.org/civicrm/drupal-php5/civicrm/profile?reset=0&gid=5
I ensured "Adams, Franklin" has a mobile phone number, but it doesn't display in the selector table.
Similarly, at: http://demo.openngo.org/civicrm/drupal-php5/user/14 the phone number isn't displayed, but it shows up in the edit mode.