Aliquot: A DOS tool to compute aliquot chains with small starting numbers, by Ivo Düntsch.
apfloat: High-performance arbitrary precision arithmetic package for C++ and Java.
ARIBAS: An interactive interpreter for big integer and multi-precision floating point arithmetic with a Pascal/Modula like syntax. It has several builtin functions for algorithmic number theory.
BIG_INT: A library of functions to handle arbitrary length integers, written on ANSI C99.
CALC: A calculator program for doing arbitrary precision integer arithmetic, written in ANSI C and Yacc, with a number of built-in functions for number theory, by Keith Matthews.
CLN - Class Library for Numbers: C++ library by Bruno Haible.
ECMNET: Elliptic curve factoring software.
Encyclopedia of Integer Sequences Seeker: EIS-Seeker is a libguile-based scheme interpreter devoted to the study of the Encyclopedia of Integer Sequences database. It is intended to help find new relations between sequences. C/Scheme, Posix.
Factorizer: A Windows program to find all factors of any positive integer less than 2^31 - 1; decompose numbers into their prime constituents; find prime numbersand pairs of primes; and to plot Erdos-Kac and Palmen Color histograms. Down load free demo, order full version online.
FTP Sites, Calculator Programs and Archives: In the Number Theory Web.
Galois: An algebra/number theory package by R. Lidl, R. W. Matthews and R. Wells.
giantint: Library of routines for large integer arithmetic and number theory.
GIMPS FAQ list: About the Mersenne Prime Freeware.
GNU MP Home Page: Free library for arbitrary precision arithmetic.
GNUBC: Supports arbitrary precision integer arithmetic calculations with interactive execution: it is a superior version of the basic bc program which comes with the UNIX operating system. Keith Matthews has written several number-theoretic programs.
HiPiLib - High Performance Libraries: Home of PIOLOGIE, a library for arbitrary precision arithmetic, operating on natural, integer and rational numbers.
Implementations of Extended LLL: By Wilberd van der Kallen.
Java PHASER Project: An application for numerically and graphically analyzing dynamical systems.
Jim Howell Software: Large integer arithmetic.
KANT / KASH: KANT is a software package for sophisticated computations in number fields and in global function fields. With KASH you are able to use the powerful KANT V4 functions within a shell.
Kaprekar Series Generator: A java application for determining the Kaprekar Constants and Series for numbers in various radixes.
L: A C++ class library, datasets and command line program for computing zeros and values of L-functions, by Michael Rubinstein.
Large Number Arithmetic in BASIC: Library for large-integer arithmetic, plus some number theory modules.
LiDIA: C++ Library For Computational Number Theory.
Magma Computational Algebra System Home Page: A large, well-supported software package for computationally hard problems in algebra, number theory, geometry and combinatorics.
MAGMA/PARI Calculator: Web interface for short programs in either language.
Maple Worksheets by John Cosgrave: A selection of Maple (V.5) worksheets for teaching purposes.
Math Archives Software: PC/Number Theory section.
Math Archives Software: Mac/Number Theory section.
Mersenne Prime Freeware: Freeware to search for Mersenne Primes. Pointers to FreeLIP, GMP, HFloat, apfloat, CALC.
MIRACL: Multiprecision Integer and Rational Arithmetic C/C++ Library.
Multiprecision Software Directory: Fortran multiprecision software by David H. Bailey of Lawrence Berkeley Lab.
NTL: A Library for doing Number Theory: A high-performance, portable C++ library providing data structures and algorithms for manipulating signed, arbitrary length integers, and for vectors, matrices, and polynomials over the integers and over finite fields.
Number Field Sieve NET: A client/server system for NFSNET by Henrik Olsen.
Number-Theoretic Hacks: Algorithms implemented by David Eppstein.
NZMATH: Python based number theory oriented calculation system, developed at Tokyo Metropolitan University. Downloads, mailing list.
p-adic Arithmetic: A Mathematica package by Stany De Smedt.
Paul's TI-92 Number Theory Archive: Download site for number theory programs adapted from UBASIC/MALM for the TI-92.
SAGE: System for Arithmetic Geometry Experimentation: a framework for number theory, algebra, and geometry, initially designed for computing with elliptic curves and modular forms, by William Stein. Open source under GPL.
Schulenberg and Associates: Factoring programs. Windows, free download.
SIMATH: Computer algebra system for number theoretic applications.
Software Packages of Interest to Number Theory: Links maintained by John Cremona.
ZEN: A toolbox for computation in finite rings, by Florent Chabaud and Reynald Lercier. ANSI-C source, free download, GPL.