Number
399
- Positive
- Odd
- Composite
- 3 digits
399 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 value399
Digit count3
Digit sum21
Digital root3repeated digit sum
PalindromicNoreads differently backwards
Happy numberNosquared-digit sums reach 1
Harshad numberYesdivisible by its own digit sum
Factors & divisors
Prime factorisation3 × 7 × 19
Distinct prime factors33, 7, 19
Number of divisors8
Sum of divisors σ(n)640
Aliquot sum241sum of the proper divisors
ClassificationDeficientthe aliquot sum is less than the number
Euler's totient φ(n)216integers below n that share no factor with it
SquarefreeYesno repeated prime factor
All divisors1, 3, 7, 19, 21, 57, 133, 3998 in total
Arithmetic
Representations
Decimal399
Binary1100011119 bits
Octal617
Hexadecimal18F
Base 36B3
Roman numeralCCCXCIX
In wordsthree hundred and ninety-nine
Ordinalthree hundred and ninety-ninth
Scientific notation3.99 × 10^2
Engineering notation399
Nearest landmarks
Powers & multiples
399 to the power 2159,201
399 to the power 363,521,199
399 to the power 425,344,958,401
399 to the power 510,112,638,401,999
First ten multiples399, 798, 1,197, 1,596, 1,995, 2,394, 2,793, 3,192, 3,591, 3,990
Powers of twoBetween 2^8 (256) and 2^9 (512)
Divisibility tests
Divisible by 2No, remainder 1
Divisible by 3Yes
Divisible by 4No, remainder 3
Divisible by 5No, remainder 4
Divisible by 6No, remainder 3
Divisible by 7Yes
Divisible by 8No, remainder 7
Divisible by 9No, remainder 3
Divisible by 10No, remainder 9
Divisible by 11No, remainder 3
Divisible by 12No, remainder 3
Divisible by 100No, remainder 99
Collatz (3n + 1) trajectory
Steps to reach 1120the total stopping time
Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven
First steps399 → 1,198 → 599 → 1,798 → 899 → 2,698 → 1,349 → 4,048 → 2,024 → 1,012 → …
Last steps… → 5 → 16 → 8 → 4 → 2 → 1
As a percentage & fraction
As a percentage39,900%
399% as a decimal3.99
399% of 100399
399% of 1,0003,990
As a fraction of 100399/100
Read another way
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Derived from 399
Other readings
Also reads as
#339999 (colour)
- #339999
- Cyan
- Dark
- Nearest: Dark cyan
#339999 is a cyan with RGB values 51, 153, 153 and HSL 180°, 50%, 40%. It is a dark colour, so black text on it reaches 6.2:1 contrast (AA for normal text). The nearest named colour is Dark cyan.
Colour values
#339999#339999
HEX#339999
HEX (short)#399
RGBrgb(51, 153, 153)
RGB (0–1)0.2, 0.6, 0.6
RGB percentages20%, 60%, 60%
HSLhsl(180, 50%, 40%)
HSV / HSBhsv(180, 66.7%, 60%)
CMYK66.7%, 0%, 0%, 40%≈naive device-independent conversion; real print needs an ICC profile
24-bit integer3,381,657
CSS custom property--colour: #339999;
Brightness & contrast
Relative luminance0.25786WCAG 2.x, 0 is black and 1 is white
Perceived brightness131.1 of 255ITU-R BT.601 weighting
Light or darkDark
Best text colour on this backgroundBlackcontrast 6.16:1
Contrast with white3.41:1WCAG normal text: Fail
Contrast with black6.16:1WCAG normal text: AA
Greyscale equivalent#838383
Inverted#CC6666
Colour vision & accessibility
Distinguishable without hueShifts in lightness toonever rely on hue alone to carry meaning
Contrast with white, large text3.41:1WCAG large text: AA
Contrast with black, large text6.16:1WCAG large text: AAA
Named colours
Hue familycyan
CSS keyword usableNo exact keyword
Colour harmonies
Complementary#993333
Analogous#339966, #336699
Triadic#993399, #999933
Split complementary#993366, #996633
Tetradic#663399, #993333, #669933
Tints, shades & saturation
Channel breakdown
R51
G153
B153
Red51 (20%)
Green153 (60%)
Blue153 (60%)
Hue180°
Saturation (HSL)50%
Lightness40%
Dominant channelGreen and Blue
Hex per channelR 33 · G 99 · B 99
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