Skandapurana 1.4.36.40

1.4.36.40

bhūmisūryāṃtaraṃ tacca bhuvarlokaḥ prakīrtitaḥ..
dhruvasūryāṃtaraṃ tacca niyutāni caturdaśa.. 38.40 ..

The space between the earth and the sun is declared to be Bhuvarloka.
The distance between Dhruva and the sun is one million four hundred thousand [yojanas];