Descobre curiosidades dos números

Na páxina de Tanya Khovanova's temos un analisador de números (ademais de moitas curiosidades, estudios, . . . de matemáticas). Fai clic no enlace Number Gossip

Así, o número 2011 é

Deficient porque a suma de todos os seus divisors positivos excepto el mesmo é menor que 2011. (Compare with perfect and abundant numbers:)
Son deficients: * ..., * 2007, * 2008, * 2009, * 2011, * 2012, * 2013, * 2014, * ...

Odd: A number is odd if it is not divisible by 2.

(Numbers that are not odd are even. Compare with another pair -- evil and odious numbers.)
* ..., * 2005, * 2007, * 2009, * 2011, * 2013, * 2015, * 2017,

Odious: The number n is odious if it has an odd number of 1's in its binary expansion.

Guess what evil numbers are.

* ..., * 2004, * 2007, * 2008, * 2011, * 2013, * 2014, * 2017, * ...

Prime: A prime is a positive integer greater than 1 that is divisible by no positive integers other than 1 and itself.

(Prime numbers are opposite to composite numbers.)
* ..., * 1997, * 1999, * 2003, * 2011, * 2017, * 2027, * 2029, * ...

Square-free
A number is said to be square-free if its prime decomposition contains no repeated factors.
* ..., * 2005, * 2006, * 2010, * 2011, * 2013, * 2014, * 2015, * ...