83A

83 is the sum of three consecutive primes (23 + 29 + 31) as well as the sum of five consecutive primes (11 + 13 + 17 + 19 + 23).

It is also the 23rd prime number, following 79 and preceding 89. 83 is a Sophie Germain prime and a safe prime, and also a Chen prime. It is an Eisenstein prime with no imaginary part and real part of the form 3n ? 1.

It is also a highly cototient number.

In Judaism when someone reaches 83 they may celebrate a "second bar mitzvah."

83 is atomic number for Bismuth, the heaviest stable element. All higher atomic numbers yield only unstable nuclei.

83 is he ISBN Group Identifier for books published in Poland.

It is also highest UHF channel on older televisions made before the late 1970s (newer televisions only go up to channel 69, due to the frequency spectrum previously assigned to channels 70-83 in the USA being re-assigned to cellular phone service there in the late 1970s-early 1980s).

The television program Lost in Space (1965-68) aired for 83 episodes.

From wikipedia and virtuescience.