Number

561

Positive
Odd
Composite
3 digits

561 is an odd 3-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 value561

Digit count3

Digit sum12

Digital root3repeated digit sum

PalindromicNoreads differently backwards

Triangular numberYes, the 33rd triangular number

Happy numberNosquared-digit sums reach 1

Harshad numberNodivisible by its own digit sum

Factors & divisors

Prime factorisation3 × 11 × 17

Distinct prime factors33, 11, 17

Number of divisors8

Sum of divisors σ(n)864

Aliquot sum303sum of the proper divisors

ClassificationDeficientthe aliquot sum is less than the number

Euler's totient φ(n)320integers below n that share no factor with it

SquarefreeYesno repeated prime factor

All divisors1, 3, 11, 17, 33, 51, 187, 5618 in total

Arithmetic

Previous number560

Next number562

Double1,122

Half280.5

Square314,721

Cube176,558,481

Square root23.685438565≈irrational, shown to 9 decimal places

Cube root8.247473974≈

Negation-561

Reciprocal0.0017825312≈

561 factorial2007227940658625152321942842706096720164… (1,301 digits)

Representations

Decimal561

Binary100011000110 bits

Octal1061

Hexadecimal231

Base 36FL

Roman numeralDLXI

In wordsfive hundred and sixty-one

Ordinalfive hundred and sixty-first

Scientific notation5.61 × 10^2

Engineering notation561

Nearest landmarks

Next prime563+2

Previous prime557−4

Distance to nearest prime2

Nearest square below529

Nearest square above576

Powers & multiples

561 to the power 2314,721

561 to the power 3176,558,481

561 to the power 499,049,307,841

561 to the power 555,566,661,698,801

First ten multiples561, 1,122, 1,683, 2,244, 2,805, 3,366, 3,927, 4,488, 5,049, 5,610

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

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 1

Divisible by 8No, remainder 1

Divisible by 9No, remainder 3

Divisible by 10No, remainder 1

Divisible by 11Yes

Divisible by 12No, remainder 9

Divisible by 100No, remainder 61

Collatz (3n + 1) trajectory

Steps to reach 143the total stopping time

Highest value reached1,6843× the starting value

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

First steps561 → 1,684 → 842 → 421 → 1,264 → 632 → 316 → 158 → 79 → 238 → …

Last steps… → 5 → 16 → 8 → 4 → 2 → 1

As a percentage & fraction

As a percentage56,100%

561% as a decimal5.61

561% of 100561

561% of 1,0005,610

As a fraction of 100561/100

Read another way

As seconds9 minutes and 21 seconds

As bytes561 B

As a 24-bit colour#000231

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Neighbouring numbers

Derived from 561

Nearby primes

#556611 (colour)

#556611
Green
Dark
Nearest: Dark olivegreen

#556611 is a green with RGB values 85, 102, 17 and HSL 72°, 71%, 23%. It is a dark colour, so white text on it reaches 6.4:1 contrast (AA for normal text). The nearest named colour is Dark olivegreen.

Open this reading on its own page →

Colour values

#556611#556611

HEX#556611

HEX (short)#561

RGBrgb(85, 102, 17)

RGB (0–1)0.3333, 0.4, 0.0667

RGB percentages33.3%, 40%, 6.7%

HSLhsl(72, 71.4%, 23.3%)

HSV / HSBhsv(72, 83.3%, 40%)

CMYK16.7%, 0%, 83.3%, 60%≈naive device-independent conversion; real print needs an ICC profile

24-bit integer5,596,689

CSS custom property--colour: #556611;

Brightness & contrast

Relative luminance0.11475WCAG 2.x, 0 is black and 1 is white

Perceived brightness91.1 of 255ITU-R BT.601 weighting

Light or darkDark

Best text colour on this backgroundWhitecontrast 6.37:1

Contrast with white6.37:1WCAG normal text: AA

Contrast with black3.29:1WCAG normal text: Fail

Greyscale equivalent#5C5C5C

Inverted#AA99EE

Colour vision & accessibility

Normal vision Protanopia Deuteranopia Tritanopia

Protanopia#6D5F00no red cones; affects about 1% of men; ΔE 15.9 from the original

Deuteranopia#6B5F1Ano green cones; the most common form, about 1% of men; ΔE 15.1 from the original

Tritanopia#5A6056no blue cones; rare, and affects men and women equally; ΔE 39.6 from the original

Distinguishable without hueYesnever rely on hue alone to carry meaning

Contrast with white, large text6.37:1WCAG large text: AAA

Contrast with black, large text3.29:1WCAG large text: AA

Named colours

Dark olivegreen · ΔE 11.5 Olivedrab · ΔE 18.9 Olive · ΔE 19.5 Dark green · ΔE 25.2 Sea green · ΔE 32.5 Forest green · ΔE 32.9

Nearest named CSS colourDark olivegreen (#556B2F)ΔE 11.52, a distinctly different colour

Hue familygreen

CSS keyword usableNo exact keyword

Colour harmonies

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

Complementary#221166

Analogous#664C11, #2B6611

Triadic#115566, #661155

Split complementary#112A66, #4D1166

Tetradic#11664D, #221166, #66112A

Tints, shades & saturation

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

Lighter +40%#CAE45F

Lighter +30%#BBDD33

Lighter +20%#9EBD20

Lighter +10%#799218

Darker −10%#313A0A

Darker −20%#0C0F02

Darker −30%#000000

Darker −40%#000000

More saturated +25%#5E7502

Less saturated −25%#4C5720

Channel breakdown

R85

G102

B17

Red85 (33.3%)

Green102 (40%)

Blue17 (6.7%)

Hue72°

Saturation (HSL)71.43%

Lightness23.33%

Dominant channelGreen

Hex per channelR 55 · G 66 · B 11

Keep nerding

Every link below is a page Nerdulator can generate from what it already knows about this value.

561

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 561

Nearby primes

Other readings

#556611 (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

Nerdulate something else