Number
981
- Positive
- Odd
- Composite
- 3 digits
981 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 value981
Digit count3
Digit sum18
Digital root9repeated digit sum
PalindromicNoreads differently backwards
Happy numberNosquared-digit sums reach 1
Harshad numberNodivisible by its own digit sum
Factors & divisors
Prime factorisation3^2 × 109
Distinct prime factors23, 109
Number of divisors6
Sum of divisors σ(n)1,430
Aliquot sum449sum of the proper divisors
ClassificationDeficientthe aliquot sum is less than the number
Euler's totient φ(n)648integers below n that share no factor with it
SquarefreeNohas a repeated prime factor
All divisors1, 3, 9, 109, 327, 9816 in total
Arithmetic
Representations
Decimal981
Binary111101010110 bits
Octal1725
Hexadecimal3D5
Base 36R9
Roman numeralCMLXXXI
In wordsnine hundred and eighty-one
Ordinalnine hundred and eighty-first
Scientific notation9.81 × 10^2
Engineering notation981
Nearest landmarks
Powers & multiples
981 to the power 2962,361
981 to the power 3944,076,141
981 to the power 4926,138,694,321
981 to the power 5908,542,059,128,901
First ten multiples981, 1,962, 2,943, 3,924, 4,905, 5,886, 6,867, 7,848, 8,829, 9,810
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 5
Divisible by 9Yes
Divisible by 10No, remainder 1
Divisible by 11No, remainder 2
Divisible by 12No, remainder 9
Divisible by 100No, remainder 81
Collatz (3n + 1) trajectory
Steps to reach 123the total stopping time
Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven
First steps981 → 2,944 → 1,472 → 736 → 368 → 184 → 92 → 46 → 23 → 70 → …
Last steps… → 5 → 16 → 8 → 4 → 2 → 1
As a percentage & fraction
As a percentage98,100%
981% as a decimal9.81
981% of 100981
981% of 1,0009,810
As a fraction of 100981/100
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Derived from 981
Other readings
Also reads as
#998811 (colour)
- #998811
- Yellow
- Dark
- Nearest: Olive
#998811 is a yellow with RGB values 153, 136, 17 and HSL 53°, 80%, 33%. It is a dark colour, so black text on it reaches 5.9:1 contrast (AA for normal text). The nearest named colour is Olive.
Colour values
#998811#998811
HEX#998811
HEX (short)#981
RGBrgb(153, 136, 17)
RGB (0–1)0.6, 0.5333, 0.0667
RGB percentages60%, 53.3%, 6.7%
HSLhsl(52.5, 80%, 33.3%)
HSV / HSBhsv(52.5, 88.9%, 60%)
CMYK0%, 11.1%, 88.9%, 40%≈naive device-independent conversion; real print needs an ICC profile
24-bit integer10,061,841
CSS custom property--colour: #998811;
Brightness & contrast
Relative luminance0.24421WCAG 2.x, 0 is black and 1 is white
Perceived brightness133.8 of 255ITU-R BT.601 weighting
Light or darkDark
Best text colour on this backgroundBlackcontrast 5.88:1
Contrast with white3.57:1WCAG normal text: Fail
Contrast with black5.88:1WCAG normal text: AA
Greyscale equivalent#838383
Inverted#6677EE
Colour vision & accessibility
Distinguishable without hueYesnever rely on hue alone to carry meaning
Contrast with white, large text3.57:1WCAG large text: AA
Contrast with black, large text5.88:1WCAG large text: AAA
Named colours
Hue familyyellow
CSS keyword usableNo exact keyword
Colour harmonies
Complementary#112299
Analogous#994411, #669911
Triadic#119988, #881199
Split complementary#116699, #441199
Tetradic#119944, #112299, #991166
Tints, shades & saturation
Channel breakdown
R153
G136
B17
Red153 (60%)
Green136 (53.3%)
Blue17 (6.7%)
Hue52.5°
Saturation (HSL)80%
Lightness33.33%
Dominant channelRed
Hex per channelR 99 · G 88 · B 11
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