0 is the
1 is the .
2 is the only even .
3 is the number of spatial dimensions we live in.
4 is the smallest number of colors sufficient to color all planar maps.
5 is the number of .
6 is the smallest .
7 is the smallest number of faces of a regular polygon that is not by straightedge and compass.
8 is the largest in the .
9 is the maximum number of that are needed to sum to any positive integer.
10 is the base of our number system.
11 is the largest known .
12 is the smallest .
13 is the number of .
14 is the smallest number n with the property that there are no numbers to n smaller numbers.
15 is the smallest n with the property that there is only one of order n.
16 is the only number of the form xy = yx with x and y different integers.
17 is the number of .
18 is the only number that is twice the sum of its digits.
19 is the maximum number of 4th powers needed to sum to any number.
20 is the number of with 6 vertices.
21 is the smallest number of distinct needed to tile a .
22 is the number of of 8.
23 is the smallest number of integer-sided boxes that tile a box so that no two boxes share a common length.
24 is the largest number divisible by all numbers less than its .
25 is the smallest that can be written as a sum of 2 .
0 is the