Number
660
- Positive
- Even
- Composite
- 3 digits
660 is an even 3-digit integer and a composite number. It has 24 divisors and a digital root of 3.
Number properties
ParityEvendivisible by 2
SignPositive
PrimalityComposite
Absolute value660
Digit count3
Digit sum12
Digital root3repeated digit sum
PalindromicNoreads differently backwards
Happy numberNosquared-digit sums reach 1
Harshad numberYesdivisible by its own digit sum
Factors & divisors
Prime factorisation2^2 × 3 × 5 × 11
Distinct prime factors42, 3, 5, 11
Number of divisors24
Sum of divisors σ(n)2,016
Aliquot sum1,356sum of the proper divisors
ClassificationAbundantthe aliquot sum exceeds the number
Euler's totient φ(n)160integers below n that share no factor with it
SquarefreeNohas a repeated prime factor
All divisors1, 2, 3, 4, 5, 6, 10, 11, 12, 15, 20, 22, 30, 33, 44, 55, 60, 66, 110, 132, 165, 220, 330, 66024 in total
Arithmetic
Representations
Decimal660
Binary101001010010 bits
Octal1224
Hexadecimal294
Base 36IC
Roman numeralDCLX
In wordssix hundred and sixty
Ordinalsix hundred and sixtieth
Scientific notation6.6 × 10^2
Engineering notation660
Nearest landmarks
Powers & multiples
660 to the power 2435,600
660 to the power 3287,496,000
660 to the power 4189,747,360,000
660 to the power 5125,233,257,600,000
First ten multiples660, 1,320, 1,980, 2,640, 3,300, 3,960, 4,620, 5,280, 5,940, 6,600
Powers of twoBetween 2^9 (512) and 2^10 (1,024)
Divisibility tests
Divisible by 2Yes
Divisible by 3Yes
Divisible by 4Yes
Divisible by 5Yes
Divisible by 6Yes
Divisible by 7No, remainder 2
Divisible by 8No, remainder 4
Divisible by 9No, remainder 3
Divisible by 10Yes
Divisible by 11Yes
Divisible by 12Yes
Divisible by 100No, remainder 60
Collatz (3n + 1) trajectory
Steps to reach 1113the total stopping time
Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven
First steps660 → 330 → 165 → 496 → 248 → 124 → 62 → 31 → 94 → 47 → …
Last steps… → 5 → 16 → 8 → 4 → 2 → 1
As a percentage & fraction
As a percentage66,000%
660% as a decimal6.6
660% of 100660
660% of 1,0006,600
As a fraction of 100660/100
Read another way
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Derived from 660
Other readings
Also reads as
#666600 (colour)
- #666600
- Yellow
- Dark
- Nearest: Olive
#666600 is a yellow with RGB values 102, 102, 0 and HSL 60°, 100%, 20%. It is a dark colour, so white text on it reaches 6.1:1 contrast (AA for normal text). The nearest named colour is Olive.
Colour values
#666600#666600
HEX#666600
HEX (short)#660
RGBrgb(102, 102, 0)
RGB (0–1)0.4, 0.4, 0
RGB percentages40%, 40%, 0%
HSLhsl(60, 100%, 20%)
HSV / HSBhsv(60, 100%, 40%)
CMYK0%, 0%, 100%, 60%≈naive device-independent conversion; real print needs an ICC profile
24-bit integer6,710,784
CSS custom property--colour: #666600;
Brightness & contrast
Relative luminance0.12328WCAG 2.x, 0 is black and 1 is white
Perceived brightness96 of 255ITU-R BT.601 weighting
Light or darkDark
Best text colour on this backgroundWhitecontrast 6.06:1
Contrast with white6.06:1WCAG normal text: AA
Contrast with black3.47:1WCAG normal text: Fail
Greyscale equivalent#5F5F5F
Inverted#9999FF
Colour vision & accessibility
Distinguishable without hueYesnever rely on hue alone to carry meaning
Contrast with white, large text6.06:1WCAG large text: AAA
Contrast with black, large text3.47:1WCAG large text: AA
Named colours
Hue familyyellow
CSS keyword usableNo exact keyword
Colour harmonies
Complementary#000066
Analogous#663300, #336600
Triadic#006666, #660066
Split complementary#003366, #330066
Tetradic#006633, #000066, #660033
Tints, shades & saturation
Channel breakdown
R102
G102
B0
Red102 (40%)
Green102 (40%)
Blue0 (0%)
Hue60°
Saturation (HSL)100%
Lightness20%
Dominant channelRed and Green
Hex per channelR 66 · G 66 · B 00
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Harmonies
Similar named colours
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