# 81

## Nearby Numbers

Positive, nonzero integers within three units

78
Seventy-Eight
79
Seventy-Nine
80
Eighty
82
Eighty-Two
83
Eighty-Three
84
Eighty-Four

## Scientific Notation

Scientific notation expresses a quantity as the product of its significand with 10 raised to an integer exponent.

## Reciprocal

A number multiplied with its reciprocal is one.

### `0.012345679012345678`

The reciprocal of 81.

## Palindrome?

A numerical palindrome has the same value when all of its digits are reversed.

The number 81 is not a palindrome.

## Not A Prime Number

A prime number is a positive integer that is divisible only by itself and one.

Eighty-one is a composite number with 5 total factors (including 1 and itself).   See primes in Base 10 Decimal

## A Composite

Composites have more than just these two factors.

Eighty-one is a composite number with 5 total factors (including 1 and itself).

## Prime Factors

The prime factors of a positive integer are the integers that divide it exactly and are also prime.

The number eighty-one has the following 1 prime factor:

3
Three

## Prime Factorization

The prime factorization of a positive integer is the unique list of prime factors together with their multiplicities

## Base Conversions

The number eighty-one in 35 different bases