not visible number in content display full or teaser

The reason this is happening is due to the default field formatter set in the field_info hook.
The formatter used does not exist and results in no field being displayed when viewing the content.

A walk around for this bug is to simply save the manage display page for the content type as this will now set the field formatter to one that exists (from the dropdown).

To fix the code you need to change the function mobile_number_field_info:

change the value set for "default_formatter" to "mobile_number_international".

'default_formatter' => 'mobile_number_international',

function mobile_number_field_info() {
  return array(
    'mobile_number' => array(
      'label' => t('Mobile Number'),
      'description' => t('This field stores mobile numbers.'),
      'settings' => array(
        'unique' => MOBILE_NUMBER_UNIQUE_NO,
      ),
      'instance_settings' => array(),
      'default_widget' => 'mobile_number_default',
      'default_formatter' => 'mobile_number_international',
      'property_type' => 'mobile_number',
      'property_callbacks' => array('mobile_number_property_callback'),
    ),
  );
}

Once applied and cache is cleared the bug will be fixed.

@namontague - Thanks for the solution. Creating a patch for the same.