The Number

21805

Twenty-One Thousand Eight Hundred and Five

In Base 18 Octodecimal Is

3d5718

The numbers with a 18 subscript use Base 18 Octodecimal notation.

For more familiar numbers: See Twenty-One Thousand Eight Hundred and Five in Base 10 Decimal

Nearby Numbers

Positive, nonzero integers within three units

21802
3d5418
Twenty-One Thousand Eight Hundred and Two in Base 18 Octodecimal
21803
3d5518
Twenty-One Thousand Eight Hundred and Three in Base 18 Octodecimal
21804
3d5618
Twenty-One Thousand Eight Hundred and Four in Base 18 Octodecimal
21806
3d5818
Twenty-One Thousand Eight Hundred and Six in Base 18 Octodecimal
21807
3d5918
Twenty-One Thousand Eight Hundred and Seven in Base 18 Octodecimal
21808
3d5a18
Twenty-One Thousand Eight Hundred and Eight in Base 18 Octodecimal

Scientific Notation

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

2.1805e4

Reciprocal

A number multiplied with its reciprocal is one.

0.0004ebf0fa0a854h18

The reciprocal of 21805 in Base 18 Octodecimal.

Palindrome?

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

The number 3d5718 is not a palindrome.

Not A Prime Number

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

Twenty-one thousand eight hundred and five is a composite number with 12 total factors (including 1 and itself).   See primes in Base 18 Octodecimal

A Composite

Composites have more than just these two factors.

Twenty-one thousand eight hundred and five is a composite number with 12 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 thousand eight hundred and five has the following 3 prime factors:

5
518
Five in Base 18 Octodecimal
7
718
Seven in Base 18 Octodecimal
89
4h18
Eighty-Nine in Base 18 Octodecimal

Prime Factorization

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

5181 · 7182 · 4h181 = 3d5718

Base Conversions

The number twenty-one thousand eight hundred and five in 35 different bases