Posts sortable column not sorting properly for custom field numbers

I have a custom field for view counts that are stored as numbers. I added a Views column, and made it sortable, but they are not sorting properly.

The results when I click on the Views column are something like this:

Views
=====
1900
10992
10004
280
18
4015
...

Here is my code:

/**
 * Add view counts to admin columns
 */
add_filter( 'manage_posts_columns', 'eri_posts_column_views' );
function eri_posts_column_views( $columns ) {
    $columns['post_views'] = 'Views';
    return $columns;
}
add_action( 'manage_posts_custom_column', 'eri_posts_custom_column_views' );
function eri_posts_custom_column_views( $column ) {
    if ( $column === 'post_views') {
        $post_id = get_the_ID();
        $meta_key = 'eri_post_view_count';
        $count = 0;
        if (get_post_meta( $post_id, $meta_key, true ) && get_post_meta( $post_id, $meta_key, true ) != '') {
            $count = get_post_meta( $post_id, $meta_key, true );
        }
        echo $count;
    }
}


/**
 * Make admin columns sortable
 */
add_filter('manage_edit-post_sortable_columns', 'eri_view_count_sortable_column');
function eri_view_count_sortable_column($columns){
    $columns['post_views'] = 'post_views';
    return $columns;
}
add_action( 'pre_get_posts', 'eri_view_count_custom_orderby' );
function eri_view_count_custom_orderby( $query ) {
    if( ! is_admin() )
        return;

    $orderby = $query->get( 'orderby');

    if( 'post_views' == $orderby ) {
      $query->set('meta_key','eri_post_view_count');
      $query->set('orderby','meta_value_num');
    }
}

I’ve tried changing meta_value_num to meta_value… not working.