As a programmer, I'm ashamed to admit that the correct answer is no. If zero was natural we wouldn't have needed 10s of thousands of years to invent it.

Zero grew up from the seeds of the undefined, just like negative numbers and people who refuse to accept that the square root only has one value. Undefined is a pathway to many abilities some would consider unnatural.

Other fun arguments in the same vein: Is atheism a religion? Is not playing golf a sport? For extra fun, try explaining the answers to both in a non-contradictory way.

Zero is a number. Need I say more?

N is the set of "counting numbers".

When you count upwards you start from 1, and go up. However, when you count down you usually end on 0. Surely this means 0 satisfies the definition.

The natural numbers are derived, according to Brouwer, from our intuition of time of time by the way. From this notion, 0 is no strange idea since it marks the moment our intuition first begins ^_^

How can nothing be a number

How about minus zero?

So 0 is hard. But you know what? Tell me what none-whole number follows right after or before 0. That's right, we don't even have a thing to call that number.