Código htaccess:
Ver original<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule ^([0-9]+)/(.+)$ archivo.php?id_archivo=$1
<filesmatch ".(jpg|JPG|gif|GIF|png|PNG|css|CSS|ico|ICO|js|JS|svg|SVG|eot|EOT|json|JSON|ttf|TTF|woff|WOFF|txt|TXT)$">
RewriteEngine Off
</filesmatch>
</IfModule>
Saludos