It's a numeral, indicating a singular quantity.
Here are some examples of how it's used:
* okati gopam (ఒకటి గోపం) - one secret
* okati pustakam (ఒకటి పుస్తకం) - one book
* okati dinamu (ఒకటి దినము) - one day
It's important to note that the pronunciation of "okati" can vary slightly depending on the context and regional dialect.