Please note that using an integer question to enter phone numbers is problematic due to the limited number of digits allowed (max 9), which may well be insufficient to store a long phone number. It is therefore recommended - for phone numbers - to use a regular text widget (which effectively has unlimited length) with an appearance=“numbers”. But this is basically only a hint to the XForm client to display a keyboard that only permits entering numbers, which depending on your platform may or may not be possible (eg Enketo cant control your laptops keyboard…). So in addition it is also recommended to add a suitable constraint regex (see above) to ensure that the user only submits numbers.
