Get search.php results in header.php?

Now, is it possible to check if page is the search page

is_search()

AND what’s the search string

is_search() AND print get_query_var( 's' )

AND how many posts were found?

is_search() AND print $GLOBALS['wp_query']->number_posts()

… or if you got a custom query…

$my_query = new WP_Query( array( /* whatever args */ ) );
is_search() AND print $my_query->number_posts()