Ping War
Digilex software company, for all your networking needs
http://www.fantastica.com/digilex/pingwar.html

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.
http://pages.prodigy.net/jhonig/bignum/

NumericalChameleon
NumericalChameleon, free Java-Software with sourcecode. Converts phys. units, radixes, roman and spoken numbers, exchange rates
http://www.jonelo.de/java/nc/

On a Generalization of Perfect Numbers
J. L. Pe introduces perfect numbers relative to an arithmetical function f. Under this scheme, the usual perfect numbers are just one among many species of "f-perfect numbers". Several open problems and examples of perfect number sets are given, as well as a few f-amicable pairs.
http://www.geocities.com/windmill96/fperfect/fperfect.html

Perfect Numbers
Harry J. Smith's pages of the mathematics behind perfect numbers, aliquot sequences and Mersenne numbers. Includes program listings and e-mail archives.
http://www.geocities.com/hjsmithh/Perfect.html

Week Numbers In Excel
Working with Week Numbers In Microsoft Excel97 and 2000. Includes both worksheet formulas and VBA code procedures.
http://www.cpearson.com/excel/weeknum.htm

Port Numbers and Services Database
Well known port numbers for TCP and UDP, from Internet Assigned Numbers Authority (IANA).
http://www.sockets.com/services.htm

An Introduction to the Theory of Numbers by Leo Moser
Textbook covering following topics: compositions and partitions; arithmetic functions; distribution of primes; irrational numbers; congruences; diophantine equations; combinatorial number theory; and geometry of numbers.
http://www.trillia.com/moser-number.html

Some Prime Numbers
A list of prime numbers.
http://www.rsok.com/~jrm/printprimes.html

Multiply Perfect Numbers
Over 2000 multiperfect numbers sorted by numerical value and by factorisation.
ftp://ftp.cs.arizona.edu/xkernel/rcs/mpfn.html