Answer

In Rāi Pratikraman, Namutthunam is generally recited 2 times.

Explanation

It comes as part of the devotional and repentance sequence where one bows with reverence to the Arihant Bhagwan and reflects on purification of faults committed during the day.

Takeaway

So, in short: Rāi Pratikraman = 2 Namutthunam.