There is no area code 338 in North America (USA, Canada, etc.).
There is no area code 632 in North America (USA, Canada, etc.).There is also no 632 prefix in area code 908.(information current as of 2012-10-16)
There is no area code 483 in North America (USA, Canada, etc.). International country code +48 is Poland.
There is no area code 139 in North America (USA, Canada, etc.). North American area codes cannot begin with 1.
There is no area code +1 851 in North America.
Area code 558 is unassigned in North America (USA, Canada, etc.). International country code +55 is Brazil.
Telephone country code +1 is North America (USA, Canada, etc.), but there is no area code 121 in North America. It is an invalid number.
North American area code +1 802 is the U.S. state of Vermont.
Area code 847 is the suburbs north of Chicago, including Evanston and Skokie. It is overlaid with area code 224.
There is no area code +1 637 in North America. Country code +63 is the Philippines.
There is no area code 523 in North America (USA, Canada, etc.). International country code +52 is Mexico.
According to NANPA, area code 748 is currently unassigned. It is not a valid area code.