Mathematical Association of America offers this article by Peterson on the hunting of perfect numbers. With hyperlinks to articles on prime numbers.

Professor at the University of La Rioja in Spain offers this reference page on aliquot sequences with a table and sequences available for viewing.

Heng O.K. explains what perfect numbers are, how to find perfect numbers, and gives info on Mersenne numbers. Follow the included exercises.

Read an introduction to multiply perfect numbers and view a table with updated information. Includes Richard Schroeppel's archive built of 2094 MPNs and a search tool.

Features a table of Aliquot cycles with links to its corresponding lists. Also find tables of orders of sociable numbers, exhaustive limits, and links to definitions.

Provides a collection of articles on the history of mathematics and includes this entry on perfect numbers. Read about Pythagoras, aliquot parts, and Euclid.

Presents a definition of the Catalan Conjecture with documentation on aliquot sequences and a detailed table. View diagrams and read a history of its projects.