WPF value binding MaskedTextBox (no mask binding)

This is my hidden text box from WPF Extended Toolkit

<xctk:MaskedTextBox Mask="(000) 000-0000" Value="{Binding Number, UpdateSourceTrigger=PropertyChanged}" />

The binding to a property includes a mask. For example, when I enter 9991114444, the property Numberhas a value of (999) 111-4444. However, I only need the cost without a mask (9991114444). Can I accomplish this with MaskedTextBox?

The number property is a property of the main line:

public string Number { get; set; }