Better still, just pack it into three unsigned bytes (2^24) and format on output. Saves 11 out of your current 14 bytes... (and just turn away anybody who has those awkward foreign phone numbers).
And same for IP addresses. An IP address will fit in four bytes once converted properly (but make your column 16 bytes so you can store IPv6 addresses as well). -- Wondering what I do? Find out at »www.digitalcon.ca Get your Obihai ATA in Canada.