SB 5.16.28
meror murdhani bhagavata atma-yoner madhyata upaklptam purim ayuta-yojana-sahasrim sama-caturasram satakaumbhim vadanti.
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In the middle of the summit of Meru is the township of Lord Brahma. Each of its four sides is calculated to extend for ten million yojanas [eighty million miles]. It is made entirely of gold, and therefore learned scholars and sages call it Satakaumbhi.