Mersenne, Marin
- Annotated portal of resources about a Frenchman, who lived during in era of Descartes and Pascal and developed a type of formula to generate certain prime numbers.
- http://primes.utm.edu/mersenne/LukeMirror/mersenne.htm

Mahler, Kurt
- Papers in PDF or PostScript. With obituary by Alf van der Poorten.
- http://oldweb.cecm.sfu.ca/Mahler/

Melfi, Giuseppe
- University of Pisa, Italy. Diophantine approximation; Modular forms; Elementary number theory; Practical numbers. Papers and thesis.
- http://www.dm.unipi.it/gauss-pages/melfi/public_html/melfi.html

Motohashi, Yoichi
- Nihon University. Analytic number theory. Publications.
- http://www.ne.jp/asahi/zeta/motohashi/

Mihailescu, Preda
- Universität-GH Paderborn. Primality proving; Computational number theory; complex and numerical analysis. Publications, thesis, software: CYCLOPROV, a LiDIA based C++ package for primality proving.
- http://www-math.uni-paderborn.de/~preda/

Marklof, Jens
- University of Bristol. Quantum Chaos, Equidistribution, Modular Forms. Publications, research projects.
- http://www.maths.bris.ac.uk/~majm/

Milne, J. S.
- Number theory, arithmetic geometry.
- http://www.jmilne.org/math/

Meuser, Diane
- Boston University. Number theory and Algebraic geometry. Contact information.
- http://math.bu.edu/people/dmm/

Murty, Kumar
- University of Toronto, Canada. Publications and resources for Number Theory courses.
- http://www.math.toronto.edu/murty/

Morain, Francois
- École Polytechnique. Computational number theory, cryptography. Papers, ECPP software.
- http://www.lix.polytechnique.fr/Labo/Francois.Morain/english-index.html

Matthews, Keith
- University of Queensland (emeritus). Computational problems, Diophantine equations, LLL, Collatz problem. Originator and maintainer of the Number Theory Web.
- http://www.maths.uq.edu.au/~krm/

Mazur, Barry
- Harvard University. Number theory, automorphic forms, arithmetic algebraic geometry. Papers and work in progress.
- http://www.math.harvard.edu/~mazur/