The total number of new followers after a year is 365*1000 = <<365*1000=365000>>365000 followers.
His total number of followers in a year is 100000+365000 = <<100000+365000=465000>>465000 followers.
If 20000 people unfollowed him, the total number of followers remaining is 465000-20000 = 445000 followers.
#### 445000