Just so happen to read this in the forum today and I also remember seeing this weird number somewhere before.
Don't call back if you get this phone number
Sep 26, 2006
IF YOU get a missed call starting with +861 (the full number is +8613713467924), do not call back.
It's the latest prank which could incur you high IDD charges unknowingly. My colleague's husband happened to return the call and it was an answering machine. He was shocked to see an enormous phone bill when he received it later. He then approached the service provider, but it could not reverse the charges. He had no choice but to pay up.
On Aug 30, I also received the same missed call.
Luckily I did not return the call as it was an anonymous phone number. So, beware of such callers.