This oneliner will show you the currently configured cache accounts for each of your Web Applications. Just paste this line of code in your SharePoint Management Shell:

Get-SPWebApplication | %{Write-Host "Web Application: " $_.url "`nSuper user: " $_.properties["portalsuperuseraccount"] "`nSuper reader: " $_.properties["portalsuperreaderaccount"] "`n"}

This is the output for the above command in my test environment:

In my case, I have not properly configured the super user accounts for all my Web Applications.

Be aware that misconfigured super user accounts can lead to access problems. You may not be able to access your SharePoint Web Application!