I submitted a paper more than one month ago. The status of my submission is still "awaiting assignment". May I ask if this is normal? How long have I to wait before formally asking the editor about the status of my submission? My field is mathematics.
It really depends on the journal. Have you been contacted by the editor upon receipt of your paper? If not, I would contact them immediately just to check up. A month is a long time to go with no word. My paper submissions (all to the Astrophysical Journal) have all been followed up by the editor within a week of initial submission.