[1] Do you know [what time the bank opens]?
[2] [What time the bank opens] is an interesting question.
In both examples, the bracketed constituent is a subordinate interrogative clause (embedded question).
It matters not whether the embedded question is complement of a verb, as in [1], or subject of the sentence. In both constructions there should be no inversion.
The meaning of [1] is:
"Do you know the answer to the question 'What time does the bank open?'"
And the meaning of [2] is:
"The answer to the question 'What time does the bank open?' is an
interesting question".