Prefix Information
The prefix 640 is part of area code 605 serving Sioux Falls, South Dakota.
This exchange contains 10,000 possible phone numbers (605-640-0000 through 605-640-9999).
Phone numbers with prefix 640 in area code 605. Location: Sioux Falls, South Dakota.
The prefix 640 is part of area code 605 serving Sioux Falls, South Dakota.
This exchange contains 10,000 possible phone numbers (605-640-0000 through 605-640-9999).