John Gill Commentary Numbers 16:49

"Now they that died by the plague were fourteen thousand and seven hundred, besides them that died about the matter of Korah." — Numbers 16:49 (ASV)

Now they that died in the plague were fourteen thousand and
seven hundred
14,700. Thus what they were threatened with, that their carcasses should fall in the wilderness, (Numbers 14:29) , was more and more fulfilled:

beside them that died about the matter of Korah ;
these are not taken into the number here, even the two hundred fifty men of Korah's company, and the families of Dathan and Abiram, (Numbers 16:32) ; how many they were is not certain, but they were but few in comparison of these.