Number

1,001

Positive
Odd
Composite
4 digits

1,001 is an odd 4-digit integer and a composite number. It has 8 divisors and a digital root of 2.

Number properties

ParityOddnot divisible by 2

SignPositive

PrimalityComposite

Absolute value1,001

Digit count4

Digit sum2

Digital root2repeated digit sum

PalindromicYesreads the same backwards

Happy numberNosquared-digit sums reach 1

Harshad numberNodivisible by its own digit sum

Factors & divisors

Prime factorisation7 × 11 × 13

Distinct prime factors37, 11, 13

Number of divisors8

Sum of divisors σ(n)1,344

Aliquot sum343sum of the proper divisors

ClassificationDeficientthe aliquot sum is less than the number

Euler's totient φ(n)720integers below n that share no factor with it

SquarefreeYesno repeated prime factor

All divisors1, 7, 11, 13, 77, 91, 143, 1,0018 in total

Arithmetic

Previous number1,000

Next number1,002

Double2,002

Half500.5

Square1,002,001

Cube1,003,003,001

Square root31.638584039≈irrational, shown to 9 decimal places

Cube root10.003332223≈

Negation-1,001

Reciprocal0.000999001≈

Representations

Decimal1,001

Binary111110100110 bits

Octal1751

Hexadecimal3E9

Base 36RT

Roman numeralMI

In wordsone thousand and one

Ordinalone thousand and first

Scientific notation1.001 × 10^3

Engineering notation1.001 × 10^3

Nearest landmarks

Next prime1,009+8

Previous prime997−4

Distance to nearest prime4

Nearest square below961

Nearest square above1,024

Powers & multiples

1,001 to the power 21,002,001

1,001 to the power 31,003,003,001

1,001 to the power 41,004,006,004,001

1,001 to the power 51,005,010,010,005,001

First ten multiples1,001, 2,002, 3,003, 4,004, 5,005, 6,006, 7,007, 8,008, 9,009, 10,010

Powers of twoBetween 2^9 (512) and 2^10 (1,024)

Divisibility tests

Divisible by 2No, remainder 1

Divisible by 3No, remainder 2

Divisible by 4No, remainder 1

Divisible by 5No, remainder 1

Divisible by 6No, remainder 5

Divisible by 7Yes

Divisible by 8No, remainder 1

Divisible by 9No, remainder 2

Divisible by 10No, remainder 1

Divisible by 11Yes

Divisible by 12No, remainder 5

Divisible by 100No, remainder 1

Collatz (3n + 1) trajectory

Steps to reach 1142the total stopping time

Highest value reached21,68821× the starting value

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

First steps1,001 → 3,004 → 1,502 → 751 → 2,254 → 1,127 → 3,382 → 1,691 → 5,074 → 2,537 → …

Last steps… → 5 → 16 → 8 → 4 → 2 → 1

As a percentage & fraction

As a percentage100,100%

1,001% as a decimal10.01

1,001% of 1001,001

1,001% of 1,00010,010

As a fraction of 1001,001/100

Read another way

As seconds16 minutes and 41 seconds

As bytes1,001 B

As a year1001 AD

As a 24-bit colour#0003E9

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Neighbouring numbers

Derived from 1,001

Nearby primes

1001 (year)

Common year
365 days
11th century
Ox

1001 was a common year of 365 days. It began on a Thursday and ended on a Thursday. Easter Sunday fell on 19 April.

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Structure of the year

Leap yearNonot divisible by 4

Days in the year365

Weeks in the year53ISO 8601 weeks; 28 December is always in the final week

Days in February28

1 January fell on aThursday

31 December fell on aThursday

Century11th century

Decade1000s

Chinese zodiacOx

Easter Sunday19 April

Months of 1001

January31 days, starts Thursday

February28 days, starts Sunday

March31 days, starts Sunday

April30 days, starts Wednesday

May31 days, starts Friday

June30 days, starts Monday

July31 days, starts Wednesday

August31 days, starts Saturday

September30 days, starts Tuesday

October31 days, starts Thursday

November30 days, starts Sunday

December31 days, starts Tuesday

Time references

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

Unix timestamp at the start-30,578,688,000

Unix timestamp at the end-30,547,152,001

Years from now1,025 years ago

Days from today374,625 days since 1 January

The number 1001

As a number1,001

In wordsone thousand and one

Roman numeralsMI

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Neighbouring years

Key dates

Also reads as

#110000 (colour)

#110000
Red
Dark
Nearest: Black

#110000 is a red with RGB values 17, 0, 0 and HSL 0°, 100%, 3%. It is a dark colour, so white text on it reaches 20.5:1 contrast (AAA for normal text). The nearest named colour is Black.

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Colour values

#110000#110000

HEX#110000

HEX (short)#100

RGBrgb(17, 0, 0)

RGB (0–1)0.0667, 0, 0

RGB percentages6.7%, 0%, 0%

HSLhsl(0, 100%, 3.3%)

HSV / HSBhsv(0, 100%, 6.7%)

CMYK0%, 100%, 100%, 93.3%≈naive device-independent conversion; real print needs an ICC profile

24-bit integer1,114,112

CSS custom property--colour: #110000;

Brightness & contrast

Relative luminance0.00119WCAG 2.x, 0 is black and 1 is white

Perceived brightness9.3 of 255ITU-R BT.601 weighting

Light or darkDark

Best text colour on this backgroundWhitecontrast 20.51:1

Contrast with white20.51:1WCAG normal text: AAA

Contrast with black1.02:1WCAG normal text: Fail

Greyscale equivalent#040404

Inverted#EEFFFF

Colour vision & accessibility

Normal vision Protanopia Deuteranopia Tritanopia

Protanopia#030200no red cones; affects about 1% of men; ΔE 4.9 from the original

Deuteranopia#070500no green cones; the most common form, about 1% of men; ΔE 5 from the original

Tritanopia#140000no blue cones; rare, and affects men and women equally; ΔE 1.3 from the original

Distinguishable without hueYesnever rely on hue alone to carry meaning

Contrast with white, large text20.51:1WCAG large text: AAA

Contrast with black, large text1.02:1WCAG large text: Fail

Named colours

Black · ΔE 5.2 Dark slate grey · ΔE 34.8 Dim grey · ΔE 43.6 Gray · ΔE 52.8 Slate grey · ΔE 53.6 Dark olivegreen · ΔE 55.6

Nearest named CSS colourBlack (#000000)ΔE 5.23, clearly different but related

Hue familyred

CSS keyword usableNo exact keyword

Colour harmonies

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

Complementary#001111

Analogous#110009, #110900

Triadic#001100, #000011

Split complementary#001109, #000911

Tetradic#091100, #001111, #090011

Tints, shades & saturation

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

Lighter +40%#DD0000

Lighter +30%#AA0000

Lighter +20%#770000

Lighter +10%#440000

Darker −10%#000000

Darker −20%#000000

Darker −30%#000000

Darker −40%#000000

More saturated +25%#110000

Less saturated −25%#0F0202

Channel breakdown

R17

Red17 (6.7%)

Green0 (0%)

Blue0 (0%)

Hue0°

Saturation (HSL)100%

Lightness3.33%

Dominant channelRed

Hex per channelR 11 · G 00 · B 00

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1,001

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 1,001

Nearby primes

Other readings

1001 (year)

Structure of the year

Months of 1001

Time references

The number 1001

Keep nerding

Neighbouring years

Key dates

#110000 (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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