Welcome to the Community Forum-it's great to see a new face here!
If you are referring to a Virgin Media account number, sometimes customers do have a six digit account number--just add zeroes in front of your account number.
If you are referring to the Virgin Mobile online account, you only need your mobile number to register the account:
just go to https://mobile.virginmedia.com/ecare/login click on register now and enter your mobile number to proceed.
Hope this helps.
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