Srimad-Bhagavatam: Canto 3 - Chapter 1 - Verse 24

Sanskrit:

स्वं स्वं कालं मनुर्भुङ्क्ते साधिकां ह्येकसप्ततिम् ॥ २४ ॥

ITRANS:

svaṁ svaṁ kālaṁ manur bhuṅktesādhikāṁ hy eka-saptatim

Translation:

Each and every Manu enjoys a life of a little more than seventy-one sets of four millenniums.

Purport:

The duration of life of a Manu comprises seventy-one sets of four millenniums, as described in the Viṣṇu Purāṇa. The duration of life of one Manu is about 852,000 years in the calculation of the demigods, or, in the calculation of human beings, 306,720,000 years.