This is not a scam. It is a Google rep (most likely working from India) who has been assigned to help with your Google Adwords account. I have had this call quite a few times and have found them to very very helpful in optimising my adWords account allowing me to maximise my campaign. They will only call if you have an adwords account - free help and advice, this is not a scam!

Received call this morning. Tried calling it back a couple of times and call was disconnected after a couple of rings. Surprisingly, this number called me again a few hours later and the 'indian accent' person on the phone was very adamant he was from Google and wanted to assist with optimising my Google Adwords. I told him to send me an email with the purpose of the call, etc.
I am still suspicious about the number.

Scammers Beware

Sales person in India stating that they are acting on behalf of Google Australia in reply to numerous emails being sent to my account.