.htaccess file permissions

What should my file permissions be for my htaccess file? I have them on 644 and when I visit the permalinks page, it’s telling me:

If your .htaccess file were writable, we could do this automatically, but it isn’t so these are the mod_rewrite rules you should have in your .htaccess file. Click in the field and press CTRL + a to select all.

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

I manually put in the code and the message is still there. How can I make it go away and what should the file permissions be?