Let the population of a city be 1,006,150 people. What is the least number of people that share a birthday?

The least number of people that share a birthday is 1, no matter what the size of the population is.

Step-by-step explanation:

Tricky Question

Suppose there is one person that has their birthday on Feb 02. It's perfectly possible that no one else in the city has their birthday on the same day, i. e. their birthdays are any time except Feb 02. So that person will be the only one who has that as a birthday. It's even possible that no one has a birthday on Feb 02, so the answer will be zero, but it's not possible to talk about sharing if no one is doing it, so the answer is

The least number of people that share a birthday is 1, no matter what the size of the population is.

Note: If this question is talking about probability calculations, then the matter is totally different.