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 1512
- 1512 is the smallest number n such that σ(x) = n has exactly 12 solutions
- 1512 is the smallest integer area of an orthic triangle of an integer-sided triangle
- 1512 is the smallest number n such that the set of digits of n + (sum of digits of n) and n + (product of digits of n) is the same as the set of digits of n (without multiplicity)
Common Properties of 1512
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.
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 number n is practical if all numbers strictly less than n are sums of distinct divisors of n.