Answer: Yes, the week as an individual unit of time, consisting of 7 days has been preserved since Creation and that is a miracle. Differing calendars sometimes had 8 and 10 day weeks, depending upon how far apart their market days were. The very word week means “seven.”
However, do not confuse “week” with “weekly cycle”. A continuous cycle of weeks has not been preserved since Creation and did not emerge as a part of calendation methods until over 3,000 years after Creation.