Prefix Information
The prefix 121 is part of area code 650 serving San Mateo, California.
This exchange contains 10,000 possible phone numbers (650-121-0000 through 650-121-9999).
Phone numbers with prefix 121 in area code 650. Location: San Mateo, California.
The prefix 121 is part of area code 650 serving San Mateo, California.
This exchange contains 10,000 possible phone numbers (650-121-0000 through 650-121-9999).