When and where did Hashem strike Ashur's camp?
Rashi: It is after he returned from fighting Kush and came to Nov, which is near Yerushalayim.
Radak citing Shir ha'Shirim Rabah 1:12: It was Pesach night.
Radak citing Seder Olam 23: It was after Chizkiyah fell ill, on the third day. That night they sang Shirah - "ha'Shir Yihyeh Lachem k'Leil Hiskadesh Chag" (Yeshayah 30:29).
Was his camp only 185,000?
Rashi: These were the troop leaders. Rashi (Yeshayah 37:36, citing Seder Olam 23) - all 185,000 were kings with crowns on their heads. Each had at least 2,000 soldiers under him (18:23-24); all of them died. Radak - Divrei ha'Yamim II, 32:21 implies like this - "va'Yachched Kol Gibor Chayil v'Nagid v'Sar b'Machaneh Melech Ashur." It says also "b'Mishmanav Razon" (Yeshayah 10:16).
Sanhedrin 95b: His camp was about 2,600,000,000 1 soldiers.
Chidushei Agados Maharal (95b): This refers to their Ko'ach Ruchni. The physical number was [less,] what is possible in the physical world. (Ko'ach Ruchni is not due to merits. Rather, Hashem decreed that they have such power, to make their downfall even more wondrous. - PF)
How were they killed?
Radak citing Sanhedrin 94a: "V'Sachas Kevodo Yekad Yekod ki'Kod Esh" - their Neshamos, which are under their actual Kavod (bodies) were burned, like the death of Nadav and Avihu.
R. Yochanan (Sanhedrin 94a): "V'Sachas Kevodo
