Number
161
- Positive
- Odd
- Composite
- 3 digits
161 is an odd 3-digit integer and a composite number. It has 4 divisors and a digital root of 8.
Number properties
ParityOddnot divisible by 2
SignPositive
PrimalityComposite
Absolute value161
Digit count3
Digit sum8
Digital root8repeated digit sum
PalindromicYesreads the same backwards
Happy numberNosquared-digit sums reach 1
Harshad numberNodivisible by its own digit sum
Factors & divisors
Prime factorisation7 × 23
Distinct prime factors27, 23
Number of divisors4
Sum of divisors σ(n)192
Aliquot sum31sum of the proper divisors
ClassificationDeficientthe aliquot sum is less than the number
Euler's totient φ(n)132integers below n that share no factor with it
SquarefreeYesno repeated prime factor
All divisors1, 7, 23, 1614 in total
Arithmetic
Representations
Decimal161
Binary101000018 bits
Octal241
HexadecimalA1
Base 364H
Roman numeralCLXI
In wordsone hundred and sixty-one
Ordinalone hundred and sixty-first
Scientific notation1.61 × 10^2
Engineering notation161
Nearest landmarks
Powers & multiples
161 to the power 225,921
161 to the power 34,173,281
161 to the power 4671,898,241
161 to the power 5108,175,616,801
First ten multiples161, 322, 483, 644, 805, 966, 1,127, 1,288, 1,449, 1,610
Powers of twoBetween 2^7 (128) and 2^8 (256)
Divisibility tests
Divisible by 2No, remainder 1
Divisible by 3No, remainder 2
Divisible by 4No, remainder 1
Divisible by 5No, remainder 1
Divisible by 6No, remainder 5
Divisible by 7Yes
Divisible by 8No, remainder 1
Divisible by 9No, remainder 8
Divisible by 10No, remainder 1
Divisible by 11No, remainder 7
Divisible by 12No, remainder 5
Divisible by 100No, remainder 61
Collatz (3n + 1) trajectory
Steps to reach 198the total stopping time
Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven
First steps161 → 484 → 242 → 121 → 364 → 182 → 91 → 274 → 137 → 412 → …
Last steps… → 5 → 16 → 8 → 4 → 2 → 1
As a percentage & fraction
As a percentage16,100%
161% as a decimal1.61
161% of 100161
161% of 1,0001,610
As a fraction of 100161/100
Read another way
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Derived from 161
Other readings
Also reads as
#116611 (colour)
- #116611
- Green
- Dark
- Nearest: Dark green
#116611 is a green with RGB values 17, 102, 17 and HSL 120°, 71%, 23%. It is a dark colour, so white text on it reaches 7.2:1 contrast (AAA for normal text). The nearest named colour is Dark green.
Colour values
#116611#116611
HEX#116611
HEX (short)#161
RGBrgb(17, 102, 17)
RGB (0–1)0.0667, 0.4, 0.0667
RGB percentages6.7%, 40%, 6.7%
HSLhsl(120, 71.4%, 23.3%)
HSV / HSBhsv(120, 83.3%, 40%)
CMYK83.3%, 0%, 83.3%, 60%≈naive device-independent conversion; real print needs an ICC profile
24-bit integer1,140,241
CSS custom property--colour: #116611;
Brightness & contrast
Relative luminance0.09662WCAG 2.x, 0 is black and 1 is white
Perceived brightness78.9 of 255ITU-R BT.601 weighting
Light or darkDark
Best text colour on this backgroundWhitecontrast 7.16:1
Contrast with white7.16:1WCAG normal text: AAA
Contrast with black2.93:1WCAG normal text: Fail
Greyscale equivalent#4E4E4E
Inverted#EE99EE
Colour vision & accessibility
Distinguishable without hueShifts in lightness toonever rely on hue alone to carry meaning
Contrast with white, large text7.16:1WCAG large text: AAA
Contrast with black, large text2.93:1WCAG large text: Fail
Named colours
Hue familygreen
CSS keyword usableNo exact keyword
Colour harmonies
Complementary#661166
Analogous#3B6611, #11663B
Triadic#111166, #661111
Split complementary#3B1166, #66113B
Tetradic#113B66, #661166, #663B11
Tints, shades & saturation
Channel breakdown
R17
G102
B17
Red17 (6.7%)
Green102 (40%)
Blue17 (6.7%)
Hue120°
Saturation (HSL)71.43%
Lightness23.33%
Dominant channelGreen
Hex per channelR 11 · G 66 · B 11
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Harmonies
Similar named colours
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