Number
909
- Positive
- Odd
- Composite
- 3 digits
909 is an odd 3-digit integer and a composite number. It has 6 divisors and a digital root of 9.
Number properties
ParityOddnot divisible by 2
SignPositive
PrimalityComposite
Absolute value909
Digit count3
Digit sum18
Digital root9repeated digit sum
PalindromicYesreads the same backwards
Happy numberNosquared-digit sums reach 1
Harshad numberNodivisible by its own digit sum
Factors & divisors
Prime factorisation3^2 × 101
Distinct prime factors23, 101
Number of divisors6
Sum of divisors σ(n)1,326
Aliquot sum417sum of the proper divisors
ClassificationDeficientthe aliquot sum is less than the number
Euler's totient φ(n)600integers below n that share no factor with it
SquarefreeNohas a repeated prime factor
All divisors1, 3, 9, 101, 303, 9096 in total
Arithmetic
Representations
Decimal909
Binary111000110110 bits
Octal1615
Hexadecimal38D
Base 36P9
Roman numeralCMIX
In wordsnine hundred and nine
Ordinalnine hundred and ninth
Scientific notation9.09 × 10^2
Engineering notation909
Nearest landmarks
Powers & multiples
909 to the power 2826,281
909 to the power 3751,089,429
909 to the power 4682,740,290,961
909 to the power 5620,610,924,483,549
First ten multiples909, 1,818, 2,727, 3,636, 4,545, 5,454, 6,363, 7,272, 8,181, 9,090
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 4
Divisible by 6No, remainder 3
Divisible by 7No, remainder 6
Divisible by 8No, remainder 5
Divisible by 9Yes
Divisible by 10No, remainder 9
Divisible by 11No, remainder 7
Divisible by 12No, remainder 9
Divisible by 100No, remainder 9
Collatz (3n + 1) trajectory
Steps to reach 115the total stopping time
Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven
First steps909 → 2,728 → 1,364 → 682 → 341 → 1,024 → 512 → 256 → 128 → 64 → …
Last steps… → 32 → 16 → 8 → 4 → 2 → 1
As a percentage & fraction
As a percentage90,900%
909% as a decimal9.09
909% of 100909
909% of 1,0009,090
As a fraction of 100909/100
Read another way
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Derived from 909
Other readings
Also reads as
#990099 (colour)
- #990099
- Magenta
- Dark
- Nearest: Dark magenta
#990099 is a magenta with RGB values 153, 0, 153 and HSL 300°, 100%, 30%. It is a dark colour, so white text on it reaches 7.5:1 contrast (AAA for normal text). The nearest named colour is Dark magenta.
Colour values
#990099#990099
HEX#990099
HEX (short)#909
RGBrgb(153, 0, 153)
RGB (0–1)0.6, 0, 0.6
RGB percentages60%, 0%, 60%
HSLhsl(300, 100%, 30%)
HSV / HSBhsv(300, 100%, 60%)
CMYK0%, 100%, 0%, 40%≈naive device-independent conversion; real print needs an ICC profile
24-bit integer10,027,161
CSS custom property--colour: #990099;
Brightness & contrast
Relative luminance0.09072WCAG 2.x, 0 is black and 1 is white
Perceived brightness98.3 of 255ITU-R BT.601 weighting
Light or darkDark
Best text colour on this backgroundWhitecontrast 7.46:1
Contrast with white7.46:1WCAG normal text: AAA
Contrast with black2.81:1WCAG normal text: Fail
Greyscale equivalent#2C2C2C
Inverted#66FF66
Colour vision & accessibility
Distinguishable without hueShifts in lightness toonever rely on hue alone to carry meaning
Contrast with white, large text7.46:1WCAG large text: AAA
Contrast with black, large text2.81:1WCAG large text: Fail
Named colours
Hue familymagenta
CSS keyword usableNo exact keyword
Colour harmonies
Complementary#009900
Analogous#4D0099, #99004D
Triadic#999900, #009999
Split complementary#4D9900, #00994D
Tetradic#994D00, #009900, #004D99
Tints, shades & saturation
Channel breakdown
R153
G0
B153
Red153 (60%)
Green0 (0%)
Blue153 (60%)
Hue300°
Saturation (HSL)100%
Lightness30%
Dominant channelRed and Blue
Hex per channelR 99 · G 00 · B 99
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Harmonies
Similar named colours
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