Invitations are sent out with your primary call in number as the default number. You can change your primary call in phone number to the be the one which is closer to you, or that you call more frequently. To change your number log into Calliflower, click on call in numbers, and use the scroller to select a new primary number.

Once you do this, all your invitations will be sent out with your primary number. Also notice that all the call invitations you receive will include your primary call in number displayed.