The default SSH port is 22, and this article explains the story behind how that port was chosen. The author, Tatu Ylonen, designed SSH in 1995 to replace telnet (port 23) and ftp (port 21). Port 22 happened to be conveniently between the ports for telnet and ftp, and Ylonen thought it would give the protocol a sense of credibility. He requested the port allocation from the Internet Assigned Numbers Authority (IANA) and received an email the next day confirming that port 22 had been assigned to SSH. The article also provides information on how to change the SSH port and configure it through firewalls. There is no controversial or surprising information in the article.
https://www.ssh.com/academy/ssh/port#the-story-of-getting-ssh-port-22