Plouffe's Inverter - Table of current records for the computation of constants

Verbose.net - Dedicated to the natural order of the universe and to the irrational and logical chaos it presents.

Inverse Symbolic Calculator - A set of programs and specialized tables of mathematical constants dedicated to the identification of real numbers.

Traveling Salesman Constants - Traveling Salesman Constants

Heilbronn Triangle Constants - Heilbronn Triangle Constants

Math Constants - Various mathematical constants in Project Gutenberg's archives.

The 27 Conspiracy - The ever-popular and still growing 27 Conspiracy is your link to the world's most mystical number!

One - A site dedicated to the number 1 and its significance on society

RJN's More Digits of Irrational Numbers - Several million digits of e, and the square roots of 2, 3, 5, 6, 7, 8, and 10.

The 47 Society - The 47 Society is an international interest-group that follows the occurence and recurrence of the quintessential random number: 47. Many suspect that the quintessential nature of 47 carries some mystical, metaphysical and/or scientific significance.

The Zero Saga and Confusions With Numbers - A discussion of the mathematical problems associated with the number zero.

73939133 - Shows what is special about the number.

The Number of the Beast - Some numerical properties of the number 666 by Mike Keith.

2001 Game - Attempts to write all integers from 1 to 100 using only the digits 2,0,0,1 and arithmetic operations.

Mathemagic - In praise of the beauty of the numbers pi, e and phi.

Seventeen and Yellow Pigs - Facts about the number 17 in history, computing, astronomy, etc.

The Sacred 37 - Lots of 37ology.

Mathematical Constants and Computation - Essays, references, links, software.

222 Divine - Some interesting facts associated with 111, the second repunit, and its multiples (including 222 and 666).

Pi Squared over Six - Dedicated to the transcendental number pi squared over six.

Number Gossip - Numerous special categories of numbers, searchable.

37 Heaven - 37-centric factoids from Tom Magliery.

About Big Numbers - Explores the world of big numbers, from thousand to googol. Identifies what objects in the universe, atoms to large scale structures, match these numbers.

Numbers, Constants and Computation - Mathematical, historical and algorithmic aspects of some classical mathematical constants.

History of the Terms Google and Googleplex - How these very large numbers (1 followed by a hundred zeroes, and 1 followed by a google of zeroes, respectively), were named, with links to references. From Swarthmore's Dr. Math.

Notable Properties of Specific Numbers - A list of numbers with interesting properties.

All Numbers Are Interesting - Attempts to determine a unique property of each integer.