.htaccess index redirect with custom 404s

DirectoryIndex index.php

Options -Indexes

RewriteEngine On

RewriteBase /

RewriteCond %{HTTP_HOST} !^(www\.example\.com)?$
RewriteRule (.*) http://www.example.com/$1 [R=301,L]

ErrorDocument 404 /customerrors/404.html


RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /index\.php\ HTTP/
RewriteRule ^index\.php$ http://www.example.com/ [R=301,L]


RewriteRule ^index\.php$ - [L]

## RewriteCond %{REQUEST_FILENAME} !-f
## RewriteCond %{REQUEST_FILENAME} !-d
## RewriteRule . /index.php [L]