Probably because it’s trained by humans and humans are more likely to choose certain numbers when they’re asked to choose randomly. 7 is a popular choice

https://www.quora.com/Why-do-people-often-pick-17-as-a-rando...

The model selects answers based on learned probabilities; for this type of question, the probability associated with "17" is relatively high, which is why it appears frequently.

hmm !

lucky number