To check your Airtel number in Nigeria, you can use either of the following methods:

1. USSD Code: Dial *121# on your Airtel line and a menu will appear on your screen. Select “Manage My Account” and then choose “My Number” from the options. Your Airtel number will be displayed on the screen.
2. Call Customer Care: Dial 111 from your Airtel line and connect with the Airtel customer care representative. Ask them to provide you with your Airtel number. They will authenticate your identity and then provide you with the number.
3. Send a Text Message: Compose a new text message and type “MYNO” (without the quotes) in the message body. Send this message to 121. Airtel will send a reply containing your Airtel number.
4. Check on the SIM Card Pack: If you have the SIM card pack or starter pack, you can find your Airtel number printed on it. Look for a set of numbers identified as the mobile number.
5. Check on Account Statements: If you have any account statements or receipts from Airtel, your number may be listed on those documents.

Remember to have your phone close by when trying these methods as you may need to input or view certain information on your screen.