If your device isn't running Windows 10, refer to the Windows 8 instructions.
From the Home screen, navigate: Settings icon (located in the lower-left) > Network & Internet. If the Windows Settings options are not visible, tap or click the Settings Home icon (located in the upper-left) to go to the Settings home page. Utilize the touchscreen (if available) or mouse to select the on-screen options.
From the left-pane, select Cellular.
From the Cellular section (located on the right), if necessary, select Verizon Wireless (LTE).
Tap or click Advanced options (located below the Data roaming options dropdown box).
From the Properties section, view the Mobile number. The available info may vary.