Number
820
- Positive
- Even
- Composite
- 3 digits
820 is an even 3-digit integer and a composite number. It has 12 divisors and a digital root of 1.
Number properties
ParityEvendivisible by 2
SignPositive
PrimalityComposite
Absolute value820
Digit count3
Digit sum10
Digital root1repeated digit sum
PalindromicNoreads differently backwards
Triangular numberYes, the 40th triangular number
Happy numberYessquared-digit sums reach 1
Harshad numberYesdivisible by its own digit sum
Factors & divisors
Prime factorisation2^2 × 5 × 41
Distinct prime factors32, 5, 41
Number of divisors12
Sum of divisors σ(n)1,764
Aliquot sum944sum of the proper divisors
ClassificationAbundantthe aliquot sum exceeds the number
Euler's totient φ(n)320integers below n that share no factor with it
SquarefreeNohas a repeated prime factor
All divisors1, 2, 4, 5, 10, 20, 41, 82, 164, 205, 410, 82012 in total
Arithmetic
Representations
Decimal820
Binary110011010010 bits
Octal1464
Hexadecimal334
Base 36MS
Roman numeralDCCCXX
In wordseight hundred and twenty
Ordinaleight hundred and twentieth
Scientific notation8.2 × 10^2
Engineering notation820
Nearest landmarks
Powers & multiples
820 to the power 2672,400
820 to the power 3551,368,000
820 to the power 4452,121,760,000
820 to the power 5370,739,843,200,000
First ten multiples820, 1,640, 2,460, 3,280, 4,100, 4,920, 5,740, 6,560, 7,380, 8,200
Powers of twoBetween 2^9 (512) and 2^10 (1,024)
Divisibility tests
Divisible by 2Yes
Divisible by 3No, remainder 1
Divisible by 4Yes
Divisible by 5Yes
Divisible by 6No, remainder 4
Divisible by 7No, remainder 1
Divisible by 8No, remainder 4
Divisible by 9No, remainder 1
Divisible by 10Yes
Divisible by 11No, remainder 6
Divisible by 12No, remainder 4
Divisible by 100No, remainder 20
Collatz (3n + 1) trajectory
Steps to reach 128the total stopping time
Highest value reached820
Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven
First steps820 → 410 → 205 → 616 → 308 → 154 → 77 → 232 → 116 → 58 → …
Last steps… → 5 → 16 → 8 → 4 → 2 → 1
As a percentage & fraction
As a percentage82,000%
820% as a decimal8.2
820% of 100820
820% of 1,0008,200
As a fraction of 100820/100
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Derived from 820
Other readings
Also reads as
#882200 (colour)
- #882200
- Orange
- Dark
- Nearest: Maroon
#882200 is a orange with RGB values 136, 34, 0 and HSL 15°, 100%, 27%. It is a dark colour, so white text on it reaches 9.2:1 contrast (AAA for normal text). The nearest named colour is Maroon.
Colour values
#882200#882200
HEX#882200
HEX (short)#820
RGBrgb(136, 34, 0)
RGB (0–1)0.5333, 0.1333, 0
RGB percentages53.3%, 13.3%, 0%
HSLhsl(15, 100%, 26.7%)
HSV / HSBhsv(15, 100%, 53.3%)
CMYK0%, 75%, 100%, 46.7%≈naive device-independent conversion; real print needs an ICC profile
24-bit integer8,921,600
CSS custom property--colour: #882200;
Brightness & contrast
Relative luminance0.06378WCAG 2.x, 0 is black and 1 is white
Perceived brightness78.8 of 255ITU-R BT.601 weighting
Light or darkDark
Best text colour on this backgroundWhitecontrast 9.23:1
Contrast with white9.23:1WCAG normal text: AAA
Contrast with black2.28:1WCAG normal text: Fail
Greyscale equivalent#353535
Inverted#77DDFF
Colour vision & accessibility
Distinguishable without hueShifts in lightness toonever rely on hue alone to carry meaning
Contrast with white, large text9.23:1WCAG large text: AAA
Contrast with black, large text2.28:1WCAG large text: Fail
Named colours
Hue familyorange
CSS keyword usableNo exact keyword
Colour harmonies
Complementary#006688
Analogous#880022, #886600
Triadic#008822, #220088
Split complementary#008866, #002288
Tetradic#228800, #006688, #660088
Tints, shades & saturation
Channel breakdown
R136
G34
B0
Red136 (53.3%)
Green34 (13.3%)
Blue0 (0%)
Hue15°
Saturation (HSL)100%
Lightness26.67%
Dominant channelRed
Hex per channelR 88 · G 22 · B 00
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