How many elders sat on thrones surrounding God's throne in Revelation 4?

Answer: 24

Around the throne were 24 other thrones, with 24 elders dressed in white and wearing golden crowns.

“Surrounding the throne were twenty-four other thrones, and on these thrones sat twenty-four elders dressed in white, with golden crowns on their heads.”— Revelation 4:4 (BSB)