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 1024
- 1024 is the number of bytes in a kilobyte
- 1024 is the smallest number which uses a proper subset of its digits in its prime factorization: 1024 = 210 — the factorization uses 1, 0, 2, and doesn't use 4
- 1024 is the smallest square with 4 different digits
- 1024 is the smallest power of 2 with the digit 0 in its decimal expansion
- 1024 is the smallest square that is concatenation of two legs of a Pythagorean triangle (102 + 242 = 262)
Rare Properties of 1024
A number is a power of 2 if it is 2 to some power.
The number n is a square if it is the square of an integer.
Common Properties of 1024
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.
The number n is odious if it has an odd number of 1's in its binary expansion.
Guess what evil numbers are.
An integer n is powerful if for every prime p dividing n, p2 also divides n.
How much power? They all can be written as a2 b3.
The number n is practical if all numbers strictly less than n are sums of distinct divisors of n.