The Number

21

Twenty-One

In Base 16 Hexadecimal Is

1516

The numbers with a 16 subscript use Base 16 Hexadecimal notation.

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

Nearby Numbers

Positive, nonzero integers within three units

18
1216
Eightteen in Base 16 Hexadecimal
19
1316
Nineteen in Base 16 Hexadecimal
20
1416
Twenty in Base 16 Hexadecimal
22
1616
Twenty-Two in Base 16 Hexadecimal
23
1716
Twenty-Three in Base 16 Hexadecimal
24
1816
Twenty-Four in Base 16 Hexadecimal

Scientific Notation

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

2.1e1

Reciprocal

A number multiplied with its reciprocal is one.

0.0c30c30c30c30c16

The reciprocal of 21 in Base 16 Hexadecimal.

Palindrome?

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

The number 1516 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 is a composite number with 4 total factors (including 1 and itself).   See primes in Base 16 Hexadecimal

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
316
Three in Base 16 Hexadecimal
7
716
Seven in Base 16 Hexadecimal

Prime Factorization

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

3161 · 7161 = 1516

Base Conversions

The number twenty-one in 35 different bases