SB 11.16.39

saṅkhyānaṁ paramāṇūnāṁ
 kālena kriyate mayā
na tathā me vibhūtīnāṁ
 sṛjato ’ṇḍāni koṭiśaḥ
Synonyms: 
saṅkhyānam — counting; parama-aṇūnām — of the atoms; kālena — after some time; kriyate — is done; mayā — by Me; na — not; tathā — in the same way; me — of Me; vibhūtīnām — of the opulences; sṛjataḥ — who am creating; aṇḍāni — universes; koṭiśaḥ — by the innumerable millions.
Translation: 
Even though over a period of time I might count all the atoms of the universe, I could not count all of My opulences which I manifest within innumerable universes.
Purport: 

The Lord here explains that Uddhava should not expect a complete catalog of the Lord’s opulences, since even the Lord Himself finds no limit to such opulences. According to Śrīla Jīva Gosvāmī, kālena indicates that the Supreme Personality of Godhead is within every atom and can therefore easily calculate the total number of atoms. However, although the Lord is certainly omniscient, even He Himself cannot supply a finite number for His opulences, because they are infinite.