Prefix Information
The prefix 400 is part of area code 650 serving San Mateo, California.
This exchange contains 10,000 possible phone numbers (650-400-0000 through 650-400-9999).
Phone numbers with prefix 400 in area code 650. Location: San Mateo, California.
The prefix 400 is part of area code 650 serving San Mateo, California.
This exchange contains 10,000 possible phone numbers (650-400-0000 through 650-400-9999).