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 1071
- 1071 is the smallest composite number ending in 1, 3, 7 or 9 that yields no primes if its first digit is changed to another non-zero digit (1071, 2071, 3071, 4071, 5071, 6071, 7071, 8071 and 9071 are all composite numbers)
Common Properties of 1071
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.
The number n is evil if it has an even number of 1's in its binary expansion.
Guess what odious numbers are.
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.