For all Mobile Broadband devices, your number can be found on your purchase receipt and on the welcome email sent to you when you first bought your device.
You can also find your number using the following methods:
On your Mobile Wi-Fi device or Data Dongle
Your number will show in the Mobile Broadband dashboard when connected to the device.
Choose Device > Diagnostics from the dashboard menu.
On your tablet
Enter the code *#100# from the phone dialler on your tablet.
On your iPad
In your settings, choose Mobile data account.