City of Denver
Directory area code 720 and prefix 521 available at City of Denver
Directory Numbers
+1 (720) 521-XXXX
Here are the components:
Country Code: +1 (both the USA and Canada share the same country code).
Area Code: A 3-digit code that designates a specific geographic area or region.
Prefix: A 3-digit code that narrows the location within the area covered by the area code.
Line Number: A 4-digit number unique to the individual or business within that prefix.