0

This number is neither prime nor composite.

The percentage of positive integers that are prime is 0%. That is, if π(n) is the number of primes less than n, then as n gets larger and larger, π(n)/n gets closer and closer to 0 (the limit is 0). [Caldwell]

The Prime Meridian is located at 0 degrees longitude. [Rupinski]

There are 0 primes p in which 0 ≡ m mod p, where m is another prime. Of course, this is a restatement of the definition of primes. [Nicholson]

Zero is nonprime and non-composite.

In any ring, for every prime there is another prime which can be added to it to get 0. Discussion of the natural primes, by contrast, does not require knowledge of 0's existence. [Merickel]

The prime ideals of height zero are the minimal prime ideals. [Nagata]

In the 586081 seven-digit prime numbers, 0 is most often the middle digit. [Gaydos]

Zero is the smallest of the k-digit numbers whose digit(s) are the number of distinct prime factors in each of the following k integers. The sequence begins 0, 1, 12, 21, 22422, 24223, 33333, 34441524, 4242436235, 23443535352, 34462443242, 35256523324, 4341535435353, 4645441523344, 5244526446515, 5335524234335, ... .

Zero is the determinant of a 4x4 matrix formed by four consecutive prime quadruplets:

  5    7   11   13 
 11   13   17   19 
101  103  107  109 
191  193  197  199.