new user account that i did not create,,, im Admin

[rcradiocontrolled]

i have a new user account (That I did not create and it has all permissions ticked ) when i right click program icons ,and look at properties and then go to security tab  there is a new user account that i did not add or create
The account say`s unknown (s-1-5-21-1408106514**** and so on and more numbers *******
Windows PowerShell see`s the account with this pasted into powershell (wmic useraccount list full) and it has full access
but i don`t see the account in the user account section of the Control Panel
https://answers.microsoft.com/en-us/windows/forum/all/account-unknown-s-1-5-21-cannot-delete-because-it/e5cc93f0-8691-453f-be4f-e991bc001190