Google Voice is a US only service for now.
Choosing an international number
It's not currently possible to select an international Google number or to forward your calls to an international number.
From Google Voice Help
You could possibly use the Google Contacts "Import" feature to create a single contact listing all 10000 phone numbers that share that 6-digit prefix. There might be a phone number limit, if so try making 10 contacts with 1000 numbers each (or 100 with 100) - then group them and block the group.
You can see the correct format for a contact with multiple ...
"The only workaround for this is to use Google Voice's call screening function. When you turn on call screening, GV will require whoever or whatever answers a forwarded call to press 1 to accept the call." Google forums
Web Skype can not call phones until you install a special plugin.
The plugin download will be shown when opening web Skype if your web browser supports it. Unfortunately it does not support ChromeOS, Linux, WinRT, and only supports a few specific browsers on Windows and Mac.
After installing that plugin, a "Call phones" button appears on web Skype:
Both Google Voice and Skype Out, and similar services, are still VOIP.
Your voice gets digitized and "carried" from your computer over the internet, until it reaches a gateway server that knows how to contact a phone number and de-digitize the info back into voice etc. But your voice is definitely making its way over IP to get to its destination (as well ...