On iOS (iPhone): Go to Settings > Phone > My Number. Your number should be displayed there.
Calling Another Phone:
The simplest method if you have access to another phone (a friend's, family member's, or even a landline). Just make a quick call or send a text message to that phone, and your number sri lanka phone number list will show up on its screen (Caller ID).
If the above methods don't work, you can call Vi customer care:
Dial 199 from your Vi number (toll-free).
Dial 198 from your Vi number (toll-free, primarily for complaints/requests). A customer service representative can tell you your number after verifying your identity.
Verizon's account PINs are generally 4 digits, not 6. If you're thinking of a 6-digit PIN, it might be a different type of PIN (e.g., a transfer PIN for porting your number, which is generated differently) or a password/voicemail PIN.
Verizon will never call or text you asking for your Account PIN. Be wary of any such requests, as they are likely scams.
Only the Account Owner can create or change the Account PIN.