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 44
- 44 is the smallest number which is the sum of a reversible pair of non-palindromic primes, 13 + 31
- 44 is the first number such that it and the next number are the product of a prime and another distinct prime squared (44 = 22*11 and 45 = 32*5)
- 44 is the smallest side of the smallest Euler brick
- There are 44 derangements of 5 objects
- There are 44 connected bipartite graphs with seven vertices
Common Properties of 44
A positive integer greater than 1 that is not prime is called composite.
Composite numbers are opposite to prime numbers.
The number n is deficient if the sum of all its positive divisors except itself is less than n.
Compare with perfect and abundant 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.
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 number n is odious if it has an odd number of 1's in its binary expansion.
Guess what evil numbers are.
A palindrome is a number that reads the same forward or backward.