Number

18,000,000,000,000,000,000

Positive
Even
Composite
20 digits

18,000,000,000,000,000,000 is an even 20-digit integer and a composite number. It has 1,140 divisors and a digital root of 9.

Number properties

ParityEvendivisible by 2

SignPositive

PrimalityComposite

Absolute value18,000,000,000,000,000,000

Digit count20

Digit sum9

Digital root9repeated digit sum

PalindromicNoreads differently backwards

Happy numberNosquared-digit sums reach 1

Harshad numberYesdivisible by its own digit sum

Factors & divisors

Prime factorisation2^19 × 3^2 × 5^18

Distinct prime factors32, 3, 5

Number of divisors1,140

Sum of divisors σ(n)64,999,938,011,166,025,725

Aliquot sum46,999,938,011,166,025,725sum of the proper divisors

ClassificationAbundantthe aliquot sum exceeds the number

Euler's totient φ(n)4,800,000,000,000,000,000integers below n that share no factor with it

SquarefreeNohas a repeated prime factor

All divisors1,140 divisors, too many to listlisting is capped at 512

Arithmetic

Previous number17,999,999,999,999,999,999

Next number18,000,000,000,000,000,001

Double36,000,000,000,000,000,000

Square324,000,000,000,000,000,000,000,000,000,000,000,000

Cube5,832,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000

Square root4,242,640,687≈irrational, shown to 9 decimal places

Cube root2,620,741≈

Negation-18,000,000,000,000,000,000

Representations

Decimal18,000,000,000,000,000,000

Binary111110011100110011011000101000011100010100001000000000000000000064 bits

Octal1747146612070502000000

HexadecimalF9CCD8A1C5080000

Base 363SR77GZYKAGW0

In wordseighteen quintillion

Ordinaleighteen quintillionth

Engineering notation18 × 10^18

Nearest landmarks

Next prime18,000,000,000,000,000,133+133

Previous prime17,999,999,999,999,999,921−79

Distance to nearest prime79

Nearest square below17,999,999,998,987,831,969

Nearest square above18,000,000,007,473,113,344

Powers & multiples

18,000,000,000,000,000,000 to the power 2324,000,000,000,000,000,000,000,000,000,000,000,000

18,000,000,000,000,000,000 to the power 3583200000000000000000000000000… (58 digits)

18,000,000,000,000,000,000 to the power 4104976000000000000000000000000… (78 digits)

18,000,000,000,000,000,000 to the power 5188956800000000000000000000000… (97 digits)

First ten multiples18,000,000,000,000,000,000, 36,000,000,000,000,000,000, 54,000,000,000,000,000,000, 72,000,000,000,000,000,000, 90,000,000,000,000,000,000, 108,000,000,000,000,000,000, 126,000,000,000,000,000,000, 144,000,000,000,000,000,000, 162,000,000,000,000,000,000, 180,000,000,000,000,000,000

Powers of twoBetween 2^63 (9,223,372,036,854,775,808) and 2^64 (18,446,744,073,709,551,616)

Divisibility tests

Divisible by 2Yes

Divisible by 3Yes

Divisible by 4Yes

Divisible by 5Yes

Divisible by 6Yes

Divisible by 7No, remainder 4

Divisible by 8Yes

Divisible by 9Yes

Divisible by 10Yes

Divisible by 11No, remainder 7

Divisible by 12Yes

Divisible by 100Yes

Collatz (3n + 1) trajectory

Steps to reach 1408the total stopping time

Highest value reached18,000,000,000,000,000,000

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

First steps18,000,000,000,000,000,000 → 9,000,000,000,000,000,000 → 4,500,000,000,000,000,000 → 2,250,000,000,000,000,000 → 1,125,000,000,000,000,000 → 562,500,000,000,000,000 → 281,250,000,000,000,000 → 140,625,000,000,000,000 → 70,312,500,000,000,000 → 35,156,250,000,000,000 → …

Last steps… → 5 → 16 → 8 → 4 → 2 → 1

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