# 101012

The numbers with a 2 subscript use Base 2 Binary notation.

For more familiar numbers: See Twenty-One in Base 10 Decimal

## Nearby Numbers

Positive, nonzero integers within three units

18
100102
Eightteen in Base 2 Binary
19
100112
Nineteen in Base 2 Binary
20
101002
Twenty in Base 2 Binary
22
101102
Twenty-Two in Base 2 Binary
23
101112
Twenty-Three in Base 2 Binary
24
110002
Twenty-Four in Base 2 Binary

## 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.

### `0.0000110000110000110000110000110000110000110000110000112`

The reciprocal of 21 in Base 2 Binary.

## Palindrome?

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

The number 101012 is a palindrome.

## Not A Prime Number

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

Twenty-one is a composite number with 4 total factors (including 1 and itself).   See primes in Base 2 Binary

## A Composite

Composites have more than just these two factors.

Twenty-one is a composite number with 4 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 twenty-one has the following 2 prime factors:

3
112
Three in Base 2 Binary
7
1112
Seven in Base 2 Binary

## Prime Factorization

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

## Base Conversions

The number twenty-one in 35 different bases