AD Computer Object Property ntsecuritydescriptor includes Owner

get-adcomputer -id <computerobject> -property ntsecuritydescriptor | select-object -expand ntsecuritydescriptor

Example:

get-adcomputer -id v2xen-15 -property ntsecuritydescriptor | select-object -expand ntsecuritydescriptor
 
Path Owner            Access
---- -----            ------
     DOMAIN\join_user NT AUTHORITY\SELF Allow  ...