Skandapurana 5.271.11

5.271.11

aṣṭāviṃśatsahasraistu vatsarāṇāṃ kṛtaṃ yugam ..
tasmiñchveto'bhavadviṣṇurbhagavānyo jagadguruḥ .. 11 ..

and twenty-eight thousand years are proclaimed as the Kṛta Yuga. / In it, the venerable Viṣṇu, who is the teacher of the world, became white. 11.