Surah Alaq (96 # in Quran) was the first surah reveled to Prophet Muhammad PBUH in Cave Hira.
because the prophet muhammed called the this surah one third of quran
I think maybe Surah Yusuf or Yunus. Maybe Yusuf more.
I'm not sure, but there is a Surah about called Nuh
surah thoor
Only one Sura is named "Muhammad".
Please read detailed explanation of Surah Yusuf in Quran.
His story appears here n there, eg Surah 7: 73-79. Sura shams also has a portion dedicated to it.
The Surah that is said to be the heart of the Quran is Yasin.
It is obviously Surah Al Kawthar Surah number 108 in the Holy Quran.
Surah Taubah is revealed without Bismillah. This signifies the detail taken into account on compililing Quran. The Quran was complied "as is" as it was revealed to prophet Muhammad PBUH.
Surah Tawba