Broken link for post whose slug consists of numbers only

I have created my first blog post on my local WordPress 6.4 installation. My post appeared on the page with the blog posts. Clicking on the title opened my post.

After that, I changed the slug of my post to a number (“12345”). This did not produce an error message. My post still appears on the page with the blob posts. However, clicking on its title now results in an error stating that the post was not found.

Why does this slug not work as a link?