Number

21,100

Positive
Even
Composite
5 digits

21,100 is an even 5-digit integer and a composite number. It has 18 divisors and a digital root of 4.

Number properties

ParityEvendivisible by 2

SignPositive

PrimalityComposite

Absolute value21,100

Digit count5

Digit sum4

Digital root4repeated digit sum

PalindromicNoreads differently backwards

Happy numberNosquared-digit sums reach 1

Harshad numberYesdivisible by its own digit sum

Factors & divisors

Prime factorisation2^2 × 5^2 × 211

Distinct prime factors32, 5, 211

Number of divisors18

Sum of divisors σ(n)46,004

Aliquot sum24,904sum of the proper divisors

ClassificationAbundantthe aliquot sum exceeds the number

Euler's totient φ(n)8,400integers below n that share no factor with it

SquarefreeNohas a repeated prime factor

All divisors1, 2, 4, 5, 10, 20, 25, 50, 100, 211, 422, 844, 1,055, 2,110, 4,220, 5,275, 10,550, 21,10018 in total

Arithmetic

Previous number21,099

Next number21,101

Double42,200

Half10,550

Square445,210,000

Cube9,393,931,000,000

Square root145.258390463≈irrational, shown to 9 decimal places

Cube root27.632964883≈

Negation-21,100

Reciprocal0.0000473934≈

Representations

Decimal21,100

Binary10100100110110015 bits

Octal51154

Hexadecimal526C

Base 36GA4

Roman numeralNot defined above 3,999there is no agreed standard notation

In wordstwenty-one thousand, one hundred

Ordinaltwenty-one thousand, one hundredth

Scientific notation2.11 × 10^4

Engineering notation21.1 × 10^3

Nearest landmarks

Next prime21,101+1

Previous prime21,089−11

Distance to nearest prime1

Nearest square below21,025

Nearest square above21,316

Powers & multiples

21,100 to the power 2445,210,000

21,100 to the power 39,393,931,000,000

21,100 to the power 4198,211,944,100,000,000

21,100 to the power 54,182,272,020,510,000,000,000

First ten multiples21,100, 42,200, 63,300, 84,400, 105,500, 126,600, 147,700, 168,800, 189,900, 211,000

Powers of twoBetween 2^14 (16,384) and 2^15 (32,768)

Divisibility tests

Divisible by 2Yes

Divisible by 3No, remainder 1

Divisible by 4Yes

Divisible by 5Yes

Divisible by 6No, remainder 4

Divisible by 7No, remainder 2

Divisible by 8No, remainder 4

Divisible by 9No, remainder 4

Divisible by 10Yes

Divisible by 11No, remainder 2

Divisible by 12No, remainder 4

Divisible by 100Yes

Collatz (3n + 1) trajectory

Steps to reach 1105the total stopping time

Highest value reached60,1002× the starting value

Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven

First steps21,100 → 10,550 → 5,275 → 15,826 → 7,913 → 23,740 → 11,870 → 5,935 → 17,806 → 8,903 → …

Last steps… → 5 → 16 → 8 → 4 → 2 → 1

As a percentage & fraction

As a percentage2,110,000%

21,100% as a decimal211

21,100% of 10021,100

21,100% of 1,000211,000

As a fraction of 10021,100/100

Read another way

As seconds5 hours, 51 minutes and 40 seconds

As bytes20.605 KiB

As a 24-bit colour#00526C

Keep nerding

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