meta_compare seems to be treating values as strings instead of integers as expected

Trying to use meta_compare as suggested in the codex:

query_posts('meta_key=miles&meta_compare=<=&meta_value=22');

Here is my code:

global $wp_query;
query_posts(
array_merge(
    array(
        'category__and' => $mycatsarray,
        'meta_key' => 'price',
        'meta_compare' => '>=',
        'meta_value' => 8500000,
        'orderby' => meta_value_num,
        'order'=>DESC
    ),
    $wp_query->query
)

);

I’m using array_merge to persist the original query. So I couldn’t quite figure out how to use the suggested syntax (‘&name=value’) for meta_compare and meta_value. Anyways, in my code the meta_value seems to be treated like a string and not an integer as expected.

Here is an example of some typical price custom fields from my custom posts:

• 8500000
• 600
• 15000
• 900
• 750
• 9000000

If it’s not a string issue, it could be that WordPress is ordering (DESC) these custom fields as follows:

1. 9000000
2. 900
3. 8500000
4. 750
5. 600
6. 15000

I would like them to be ordered (DESC) as follows:

1. 9000000
2. 8500000
3. 15000
4. 900
5. 750
6. 600

Am I doing something wrong here?