Numbers 16:2

2 and rose up against Moses. With them were 250 Israelite men, well-known community leaders who had been appointed members of the council.

Read Numbers 16:2 Using Other Translations

And they rose up before Moses, with certain of the children of Israel, two hundred and fifty princes of the assembly, famous in the congregation, men of renown:
And they rose up before Moses, with a number of the people of Israel, 250 chiefs of the congregation, chosen from the assembly, well-known men.
They incited a rebellion against Moses, along with 250 other leaders of the community, all prominent members of the assembly.