"There are 14 manvantara-avatāras in one day of Brahmā, 420 in one month, and 5,040 in one year.
Sri Caitanya-caritamrta > Cc. Madhya-lila > Madhya 20: Lord Sri Caitanya Mahaprabhu Instructs Sanatana Gosvami in the Science of the Absolute Truth > TEXT 321