Number

2,001

Positive
Odd
Composite
4 digits

2,001 is an odd 4-digit integer and a composite number. It has 8 divisors and a digital root of 3.

Number properties

ParityOddnot divisible by 2

SignPositive

PrimalityComposite

Absolute value2,001

Digit count4

Digit sum3

Digital root3repeated digit sum

PalindromicNoreads differently backwards

Happy numberNosquared-digit sums reach 1

Harshad numberYesdivisible by its own digit sum

Factors & divisors

Prime factorisation3 × 23 × 29

Distinct prime factors33, 23, 29

Number of divisors8

Sum of divisors σ(n)2,880

Aliquot sum879sum of the proper divisors

ClassificationDeficientthe aliquot sum is less than the number

Euler's totient φ(n)1,232integers below n that share no factor with it

SquarefreeYesno repeated prime factor

All divisors1, 3, 23, 29, 69, 87, 667, 2,0018 in total

Arithmetic

Previous number2,000

Next number2,002

Double4,002

Half1,000.5

Square4,004,001

Cube8,012,006,001

Square root44.732538493≈irrational, shown to 9 decimal places

Cube root12.601310017≈

Negation-2,001

Reciprocal0.0004997501≈

Representations

Decimal2,001

Binary1111101000111 bits

Octal3721

Hexadecimal7D1

Base 361JL

Roman numeralMMI

In wordstwo thousand and one

Ordinaltwo thousand and first

Scientific notation2.001 × 10^3

Engineering notation2.001 × 10^3

Nearest landmarks

Next prime2,003+2

Previous prime1,999−2

Distance to nearest prime2

Nearest square below1,936

Nearest square above2,025

Powers & multiples

2,001 to the power 24,004,001

2,001 to the power 38,012,006,001

2,001 to the power 416,032,024,008,001

2,001 to the power 532,080,080,040,010,001

First ten multiples2,001, 4,002, 6,003, 8,004, 10,005, 12,006, 14,007, 16,008, 18,009, 20,010

Powers of twoBetween 2^10 (1,024) and 2^11 (2,048)

Divisibility tests

Divisible by 2No, remainder 1

Divisible by 3Yes

Divisible by 4No, remainder 1

Divisible by 5No, remainder 1

Divisible by 6No, remainder 3

Divisible by 7No, remainder 6

Divisible by 8No, remainder 1

Divisible by 9No, remainder 3

Divisible by 10No, remainder 1

Divisible by 11No, remainder 10

Divisible by 12No, remainder 9

Divisible by 100No, remainder 1

Collatz (3n + 1) trajectory

Steps to reach 150the total stopping time

Highest value reached6,0043× the starting value

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

First steps2,001 → 6,004 → 3,002 → 1,501 → 4,504 → 2,252 → 1,126 → 563 → 1,690 → 845 → …

Last steps… → 5 → 16 → 8 → 4 → 2 → 1

As a percentage & fraction

As a percentage200,100%

2,001% as a decimal20.01

2,001% of 1002,001

2,001% of 1,00020,010

As a fraction of 1002,001/100

Read another way

As seconds33 minutes and 21 seconds

As bytes1.954 KiB

As a year2001 AD

As a 24-bit colour#0007D1

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Neighbouring numbers

Derived from 2,001

Nearby primes

2001 (year)

Common year
365 days
21st century
Snake

2001 was a common year of 365 days. It began on a Monday and ended on a Monday. Easter Sunday fell on 15 April.

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Structure of the year

Leap yearNonot divisible by 4

Days in the year365

Weeks in the year52ISO 8601 weeks; 28 December is always in the final week

Days in February28

1 January fell on aMonday

31 December fell on aMonday

Century21st century

Decade2000s

Chinese zodiacSnake

Easter Sunday15 April

Months of 2001

January31 days, starts Monday

February28 days, starts Thursday

March31 days, starts Thursday

April30 days, starts Sunday

May31 days, starts Tuesday

June30 days, starts Friday

July31 days, starts Sunday

August31 days, starts Wednesday

September30 days, starts Saturday

October31 days, starts Monday

November30 days, starts Thursday

December31 days, starts Saturday

Time references

These values depend on today’s date and change daily.

Unix timestamp at the start978,307,200

Unix timestamp at the end1,009,843,199

Years from now25 years ago

Days from today9,382 days since 1 January

The number 2001

As a number2,001

In wordstwo thousand and one

Roman numeralsMMI

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Neighbouring years

Key dates

Also reads as

#220000 (colour)

#220000
Red
Dark
Nearest: Black

#220000 is a red with RGB values 34, 0, 0 and HSL 0°, 100%, 7%. It is a dark colour, so white text on it reaches 19.7:1 contrast (AAA for normal text). The nearest named colour is Black.

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Colour values

#220000#220000

HEX#220000

HEX (short)#200

RGBrgb(34, 0, 0)

RGB (0–1)0.1333, 0, 0

RGB percentages13.3%, 0%, 0%

HSLhsl(0, 100%, 6.7%)

HSV / HSBhsv(0, 100%, 13.3%)

CMYK0%, 100%, 100%, 86.7%≈naive device-independent conversion; real print needs an ICC profile

24-bit integer2,228,224

CSS custom property--colour: #220000;

Brightness & contrast

Relative luminance0.0034WCAG 2.x, 0 is black and 1 is white

Perceived brightness18.6 of 255ITU-R BT.601 weighting

Light or darkDark

Best text colour on this backgroundWhitecontrast 19.66:1

Contrast with white19.66:1WCAG normal text: AAA

Contrast with black1.07:1WCAG normal text: Fail

Greyscale equivalent#070707

Inverted#DDFFFF

Colour vision & accessibility

Normal vision Protanopia Deuteranopia Tritanopia

Protanopia#080600no red cones; affects about 1% of men; ΔE 14.4 from the original

Deuteranopia#120E00no green cones; the most common form, about 1% of men; ΔE 14.4 from the original

Tritanopia#270000no blue cones; rare, and affects men and women equally; ΔE 4 from the original

Distinguishable without hueYesnever rely on hue alone to carry meaning

Contrast with white, large text19.66:1WCAG large text: AAA

Contrast with black, large text1.07:1WCAG large text: Fail

Named colours

Black · ΔE 14.9 Dark slate grey · ΔE 39 Dim grey · ΔE 43.8 Saddle brown · ΔE 51.5 Gray · ΔE 52.6 Maroon · ΔE 52.7

Nearest named CSS colourBlack (#000000)ΔE 14.93, a distinctly different colour

Hue familyred

CSS keyword usableNo exact keyword

Colour harmonies

base +30°+90°+120°+180°+210°+240°+270°+330°

Complementary#002222

Analogous#220011, #221100

Triadic#002200, #000022

Split complementary#002211, #001122

Tetradic#112200, #002222, #110022

Tints, shades & saturation

+40%+30%+20%+10%base -10%-20%-30%-40%

Lighter +40%#EE0000

Lighter +30%#BB0000

Lighter +20%#880000

Lighter +10%#550000

Darker −10%#000000

Darker −20%#000000

Darker −30%#000000

Darker −40%#000000

More saturated +25%#220000

Less saturated −25%#1E0404

Channel breakdown

R34

Red34 (13.3%)

Green0 (0%)

Blue0 (0%)

Hue0°

Saturation (HSL)100%

Lightness6.67%

Dominant channelRed

Hex per channelR 22 · G 00 · B 00

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2,001

Number properties

Factors & divisors

Arithmetic

Representations

Nearest landmarks

Powers & multiples

Divisibility tests

Collatz (3n + 1) trajectory

As a percentage & fraction

Read another way

Keep nerding

Neighbouring numbers

Derived from 2,001

Nearby primes

Other readings

2001 (year)

Structure of the year

Months of 2001

Time references

The number 2001

Keep nerding

Neighbouring years

Key dates

#220000 (colour)

Colour values

Brightness & contrast

Colour vision & accessibility

Named colours

Colour harmonies

Tints, shades & saturation

Channel breakdown

Keep nerding

Harmonies

Lighter and darker

Similar named colours

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