I applied for a job online about a month and a half ago and received no response. The company is still posting job ads, should I apply again?

I assume they didn’t respond because they didn’t think I was a good fit for the position. Could I just apply for it again? Or do I send them an email telling them that I noticed that the position might not have been filled yet, and reiterate how qualified I feel I am?

Or do I do nothing. What is the professional thing to do here?