Английская Википедия:253 (number)
Материал из Онлайн справочника
Шаблон:Infobox number 253 (two hundred [and] fifty-three) is the natural number following 252 and preceding 254.
In mathematics
253 is:
- a semiprime since it is the product of 2 primes.
- a triangular number.[1]
- a star number.[2]
- a centered heptagonal number.[3]
- a centered nonagonal number.[4]
- a Blum integer.[5]
- a member of the 13-aliquot tree.
<math>10^{506}-10^{253}-1</math> is a prime number.
References
