olemus
matemaatika haru, mis uurib täisarve ja nende omadusi,
nüüdisaegse krüptograafia põhiline alusdistsipliin

Wiktionary:
(mathematics) the branch of pure mathematics concerned with the properties of integers

ülevaateid
https://www.codechef.com/wiki/tutorial-number-theory/

https://www.math.brown.edu/~jhs/frint.html

https://crypto.stanford.edu/pbc/notes/numbertheory/

https://en.wikipedia.org/wiki/Number_theory

https://en.wikipedia.org/wiki/Algebraic_number_theory

https://en.wikipedia.org/wiki/List_of_number_theory_topics

https://en.wikipedia.org/wiki/Category:Number_theory

https://wstein.org/129/ant/html/

http://www2.math.uu.se/~lal/kompendier/Talteori.pdf

https://www.saylor.org/site/wp-content/uploads/2013/05/An-Introductory-in-Elementary-Number-Theory.pdf

http://www.freebookcentre.net/Mathematics/Number-Theory-Books.html