It's not, most likely. A working 2-factor scheme needs two devices and communication channels to the end user that are completely independent of each other. If

It's not, most likely. A working 2-factor scheme needs two devices and communication channels to the end user that are completely independent of each other. If your mobile phone links to an account somewhere (e.g. Google account) that you can also access from the other device (e.g. a PC), and security-related settings can be changed from the other device, too, then that's insecure out-of-the-box.