Number
213
- Positive
- Odd
- Composite
- 3 digits
213 is an odd 3-digit integer and a composite number. It has 4 divisors and a digital root of 6.
Number properties
ParityOddnot divisible by 2
SignPositive
PrimalityComposite
Absolute value213
Digit count3
Digit sum6
Digital root6repeated digit sum
PalindromicNoreads differently backwards
Happy numberNosquared-digit sums reach 1
Harshad numberNodivisible by its own digit sum
Factors & divisors
Prime factorisation3 × 71
Distinct prime factors23, 71
Number of divisors4
Sum of divisors σ(n)288
Aliquot sum75sum of the proper divisors
ClassificationDeficientthe aliquot sum is less than the number
Euler's totient φ(n)140integers below n that share no factor with it
SquarefreeYesno repeated prime factor
All divisors1, 3, 71, 2134 in total
Arithmetic
Representations
Decimal213
Binary110101018 bits
Octal325
HexadecimalD5
Base 365X
Roman numeralCCXIII
In wordstwo hundred and thirteen
Ordinaltwo hundred and thirteenth
Scientific notation2.13 × 10^2
Engineering notation213
Nearest landmarks
Powers & multiples
213 to the power 245,369
213 to the power 39,663,597
213 to the power 42,058,346,161
213 to the power 5438,427,732,293
First ten multiples213, 426, 639, 852, 1,065, 1,278, 1,491, 1,704, 1,917, 2,130
Powers of twoBetween 2^7 (128) and 2^8 (256)
Divisibility tests
Divisible by 2No, remainder 1
Divisible by 3Yes
Divisible by 4No, remainder 1
Divisible by 5No, remainder 3
Divisible by 6No, remainder 3
Divisible by 7No, remainder 3
Divisible by 8No, remainder 5
Divisible by 9No, remainder 6
Divisible by 10No, remainder 3
Divisible by 11No, remainder 4
Divisible by 12No, remainder 9
Divisible by 100No, remainder 13
Collatz (3n + 1) trajectory
Steps to reach 113the total stopping time
Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven
First steps213 → 640 → 320 → 160 → 80 → 40 → 20 → 10 → 5 → 16 → …
Last steps… → 5 → 16 → 8 → 4 → 2 → 1
As a percentage & fraction
As a percentage21,300%
213% as a decimal2.13
213% of 100213
213% of 1,0002,130
As a fraction of 100213/100
Read another way
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Derived from 213
Other readings
Also reads as
#221133 (colour)
- #221133
- Violet
- Dark
- Nearest: Black
#221133 is a violet with RGB values 34, 17, 51 and HSL 270°, 50%, 13%. It is a dark colour, so white text on it reaches 17.6:1 contrast (AAA for normal text). The nearest named colour is Black.
Colour values
#221133#221133
HEX#221133
HEX (short)#213
RGBrgb(34, 17, 51)
RGB (0–1)0.1333, 0.0667, 0.2
RGB percentages13.3%, 6.7%, 20%
HSLhsl(270, 50%, 13.3%)
HSV / HSBhsv(270, 66.7%, 20%)
CMYK33.3%, 66.7%, 0%, 80%≈naive device-independent conversion; real print needs an ICC profile
24-bit integer2,232,627
CSS custom property--colour: #221133;
Brightness & contrast
Relative luminance0.0098WCAG 2.x, 0 is black and 1 is white
Perceived brightness28.5 of 255ITU-R BT.601 weighting
Light or darkDark
Best text colour on this backgroundWhitecontrast 17.56:1
Contrast with white17.56:1WCAG normal text: AAA
Contrast with black1.2:1WCAG normal text: Fail
Greyscale equivalent#171717
Inverted#DDEECC
Colour vision & accessibility
Distinguishable without hueYesnever rely on hue alone to carry meaning
Contrast with white, large text17.56:1WCAG large text: AAA
Contrast with black, large text1.2:1WCAG large text: Fail
Named colours
Hue familyviolet
CSS keyword usableNo exact keyword
Colour harmonies
Complementary#223311
Analogous#111133, #331133
Triadic#332211, #113322
Split complementary#333311, #113311
Tetradic#331111, #223311, #113333
Tints, shades & saturation
Channel breakdown
R34
G17
B51
Red34 (13.3%)
Green17 (6.7%)
Blue51 (20%)
Hue270°
Saturation (HSL)50%
Lightness13.33%
Dominant channelBlue
Hex per channelR 22 · G 11 · B 33
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Harmonies
Similar named colours
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