# 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 83

- There are exactly 83 right-truncatable primes
- 83 is the smallest multi-digit prime consisting of only curved digits
- 83 is the smallest prime number which is the sum of a prime number of consecutive primes in a prime number of different ways (verified by Christopher Heckman)
- 83 is the smallest nontrivial integer whose square (6889) is a strobogrammatic number

## Common Properties of 83

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.

A *prime* is a positive integer greater than 1 that is divisible by no positive integers other than 1 and itself.

Prime numbers are opposite to composite numbers.

A number is said to be *square-free* if its prime decomposition contains no repeated factors.