Surah Al-Kahf, ayah 11

فَضَرَبۡنَا عَلَىٰٓ ءَاذَانِهِمۡ فِي ٱلۡكَهۡفِ سِنِينَ عَدَدٗا ١١

Fadarabnā 'alā ādhānihim fil-kahfi sinīna 'adadā

So We cast [a cover of sleep] over their ears within the cave for a number of years.