Number Gossip
(Enter a number and I'll tell you everything you wanted to know about it but were afraid to ask.)
Unique Properties of 836
- 836 is the numerical equivalent of the word TEN on a touch-tone telephone
- 836 is the smallest number such that its square is a palindrome with an even number of digits
- 836 is the smallest weird untouchable number
- 836 is the smallest evil weird number (submitted by Massimo Kofler)
Rare Properties of 836
The number n is called a weird number if it is abundant but is not the sum of any subset of its proper factors.
Common Properties of 836
The number n is abundant if the sum of all its positive divisors except itself is more than n.
They are abundant above perfection, not to mention deficiency. See perfect and deficient numbers.
The number n is called an apocalyptic power if 2n contains the consecutive digits 666 (in decimal).
A positive integer greater than 1 that is not prime is called composite.
Composite numbers are opposite to prime numbers.
A number is even if it is divisible by 2.
Numbers that are not even are odd. Compare with another pair -- evil and odious numbers.
The number n is evil if it has an even number of 1's in its binary expansion.
Guess what odious numbers are.
One can take the sum of the squares of the digits of a number. Those numbers are happy for which iterating this operation eventually leads to 1.
The untouchable numbers are those that are not the sum of the proper divisors of any number.