It is, in terms of population, one of the smallest area codes in North America, with only about 320,000 people in the region served by 906. It was created as a spilt from 616 in 1961, as a flash-cut, with no official permissive dialing period.

Police call: This is officer Morgan and we have another 906.
Police response: Is the area confined to direct sunlight?
Police call: Affirmative.
Police response: Sending dispatch.

Officer #1: Sir, we got a 906 on our hands.
Officer #2: Ah, the old 906. Vampire attack, as everyone knows. Saw one back when I was a rookie.