Yes, a URL can be just numbers, but it is less common and not recommended. An address with only numbers might look like this: https://123.456.789.101/some-page
In this example, the domain part of the URL consists of an IP address (123.456.789.101), which is a series of numbers separated by periods. While it's technically possible to use an IP address as a URL, it is generally not user-friendly and could lead to confusion.