Number
642
- Positive
- Even
- Composite
- 3 digits
642 is an even 3-digit integer and a composite number. It has 8 divisors and a digital root of 3.
Number properties
ParityEvendivisible by 2
SignPositive
PrimalityComposite
Absolute value642
Digit count3
Digit sum12
Digital root3repeated digit sum
PalindromicNoreads differently backwards
Happy numberNosquared-digit sums reach 1
Harshad numberNodivisible by its own digit sum
Factors & divisors
Prime factorisation2 × 3 × 107
Distinct prime factors32, 3, 107
Number of divisors8
Sum of divisors σ(n)1,296
Aliquot sum654sum of the proper divisors
ClassificationAbundantthe aliquot sum exceeds the number
Euler's totient φ(n)212integers below n that share no factor with it
SquarefreeYesno repeated prime factor
All divisors1, 2, 3, 6, 107, 214, 321, 6428 in total
Arithmetic
Representations
Decimal642
Binary101000001010 bits
Octal1202
Hexadecimal282
Base 36HU
Roman numeralDCXLII
In wordssix hundred and forty-two
Ordinalsix hundred and forty-second
Scientific notation6.42 × 10^2
Engineering notation642
Nearest landmarks
Powers & multiples
642 to the power 2412,164
642 to the power 3264,609,288
642 to the power 4169,879,162,896
642 to the power 5109,062,422,579,232
First ten multiples642, 1,284, 1,926, 2,568, 3,210, 3,852, 4,494, 5,136, 5,778, 6,420
Powers of twoBetween 2^9 (512) and 2^10 (1,024)
Divisibility tests
Divisible by 2Yes
Divisible by 3Yes
Divisible by 4No, remainder 2
Divisible by 5No, remainder 2
Divisible by 6Yes
Divisible by 7No, remainder 5
Divisible by 8No, remainder 2
Divisible by 9No, remainder 3
Divisible by 10No, remainder 2
Divisible by 11No, remainder 4
Divisible by 12No, remainder 6
Divisible by 100No, remainder 42
Collatz (3n + 1) trajectory
Steps to reach 125the total stopping time
Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven
First steps642 → 321 → 964 → 482 → 241 → 724 → 362 → 181 → 544 → 272 → …
Last steps… → 5 → 16 → 8 → 4 → 2 → 1
As a percentage & fraction
As a percentage64,200%
642% as a decimal6.42
642% of 100642
642% of 1,0006,420
As a fraction of 100642/100
Read another way
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Derived from 642
Other readings
Also reads as
#664422 (colour)
- #664422
- Orange
- Dark
- Nearest: Saddle brown
#664422 is a orange with RGB values 102, 68, 34 and HSL 30°, 50%, 27%. It is a dark colour, so white text on it reaches 8.7:1 contrast (AAA for normal text). The nearest named colour is Saddle brown.
Colour values
#664422#664422
HEX#664422
HEX (short)#642
RGBrgb(102, 68, 34)
RGB (0–1)0.4, 0.2667, 0.1333
RGB percentages40%, 26.7%, 13.3%
HSLhsl(30, 50%, 26.7%)
HSV / HSBhsv(30, 66.7%, 40%)
CMYK0%, 33.3%, 66.7%, 60%≈naive device-independent conversion; real print needs an ICC profile
24-bit integer6,702,114
CSS custom property--colour: #664422;
Brightness & contrast
Relative luminance0.07075WCAG 2.x, 0 is black and 1 is white
Perceived brightness77.2 of 255ITU-R BT.601 weighting
Light or darkDark
Best text colour on this backgroundWhitecontrast 8.7:1
Contrast with white8.7:1WCAG normal text: AAA
Contrast with black2.41:1WCAG normal text: Fail
Greyscale equivalent#494949
Inverted#99BBDD
Colour vision & accessibility
Distinguishable without hueYesnever rely on hue alone to carry meaning
Contrast with white, large text8.7:1WCAG large text: AAA
Contrast with black, large text2.41:1WCAG large text: Fail
Named colours
Hue familyorange
CSS keyword usableNo exact keyword
Colour harmonies
Complementary#224466
Analogous#662222, #666622
Triadic#226644, #442266
Split complementary#226666, #222266
Tetradic#226622, #224466, #662266
Tints, shades & saturation
Channel breakdown
R102
G68
B34
Red102 (40%)
Green68 (26.7%)
Blue34 (13.3%)
Hue30°
Saturation (HSL)50%
Lightness26.67%
Dominant channelRed
Hex per channelR 66 · G 44 · B 22
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Harmonies
Similar named colours
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