BVN simply stands for Bank Verification Number. There can be millions of reasons why you want to have a way to check your BVN like maybe you have forgotten it or want to use it urgently.
To check you BVN dail *565*0#
Now, this is the general USSD code to check your BVN from your mobile line you used in registering with the BVN assigned to you.
Making a request to check your BVN for any of your bank, it will cost you 20naira from your mobile network, either MTN, Glo, 9mobile or Airtel. This charge will be done for as many times as you did run the USSD code, so use it wisely.