ssh on port 21?

[rab <rab nauticom net>]

I can telnet out through the firewall at work but I can't get them to 
allow me to ssh out to my home pc. Can I open a hole in my router 
firewall and allow incoming ssh on both ports 21 and 22? (I'm able to 
ssh into my pc using dial up but not through the company lan.)

Rick B.