Numbers 31:8
וְאֶת מַלְכֵי מִדְיָן הָרְגוּ עַל חַלְלֵיהֶם אֶת אֱוִי וְאֶת רֶקֶם וְאֶ תצוּר וְאֶת חוּר וְאֶת רֶבַע חֲמֵשֶׁת מַלְכֵי מִדְיָן וְאֵת בִּלְעָם בֶּן בְּעוֹר הָרְגוּ בֶּחָרֶב
They killed the kings of Midian with the rest of the fallen: Evi, Rekem, Tzur, Chur and Reva, the five kings of Midian; they also slew Balaam the son of Beor with the sword.
In Talmud Sanhedrin 106b, a heretic asked Rabbi Chanina how long Balaam lived. Rabbi Chaninah replied, “I haven’t seen anything specific on the matter but since Psalms 55:24 says that bloodthirsty and deceitful people will not live out even half their days, I would guess that he was 33 or 34.” The heretic replied, “That’s right! The chronicles of Balaam say that he was 33 when he was killed by Pinchas.”