Recognised as Number
121,720
- Positive
- Even
- Composite
- 6 digits
121,720 is an even 6-digit integer and a composite number. It has 32 divisors and a digital root of 4.
Number properties
ParityEvendivisible by 2
SignPositive
PrimalityComposite
Absolute value121,720
Digit count6
Digit sum13
Digit product0zero, because one of the digits is zero
Multiplicative persistence1times the digit product can be taken before one digit is left
Digital root4repeated digit sum
PalindromicNoreads differently backwards
Happy numberNosquared-digit sums reach 1
Harshad numberNodivisible by its own digit sum
Factors & divisors
Prime factorisation2^3 × 5 × 17 × 179
Distinct prime factors42, 5, 17, 179
Number of divisors32
Sum of divisors σ(n)291,600
Aliquot sum169,880sum of the proper divisors
ClassificationAbundantthe aliquot sum exceeds the number
Euler's totient φ(n)45,568integers below n that share no factor with it
Carmichael function λ(n)1,424the smallest exponent with aˣ ≡ 1 for every unit; smaller than φ(n) = 45,568
Möbius function μ(n)0zero, because a prime divides n twice
SquarefreeNohas a repeated prime factor
All divisors1, 2, 4, 5, 8, 10, 17, 20, 34, 40, 68, 85, 136, 170, 179, 340, 358, 680, 716, 895, 1,432, 1,790, 3,043, 3,580, 6,086, 7,160, 12,172, 15,215, 24,344, 30,430, 60,860, 121,72032 in total
Arithmetic
Representations
Decimal121,720
Binary1110110110111100017 bits
Octal355570
Hexadecimal1DB78
Base 362LX4
Roman numeralNot defined above 3,999there is no agreed standard notation
In wordsone hundred and twenty-one thousand, seven hundred and twenty
Ordinalone hundred and twenty-one thousand, seven hundred and twentieth
Scientific notation1.2172 × 10^5
Engineering notation121.72 × 10^3
In other bases
Ternary20011222011base 3; the most digit-efficient integer base after e: 11 digits
Quinary12343340base 5; one hand: 8 digits
Septenary1014604base 7: 7 digits
Nonary204864base 9; each digit is two ternary digits: 6 digits
Duodecimal5a534base 12; divides by 2, 3, 4 and 6, which is why eggs and inches come in twelves: 5 digits
Vigesimalf460base 20; hands and feet, and the Mayan and Yoruba systems: 4 digits
Sexagesimal33:48:40base 60; Babylonian, and still how an hour and a circle are divided: 3 digits
Balanced ternary1T01TT00T011digits −1, 0 and +1 written T, 0 and 1; negation is swapping T and 1, so no sign is needed
Negabinary1100010110010001000base −2; place values alternate 1, −2, 4, −8, so every integer has exactly one form without a sign
Bit-level
00000000000000011101101101111000
Bit length17 bitsto write the magnitude
Set bits11the population count, or Hamming weight
Zero bits6within that length
Bit parityodd11 set bits, so odd; not the same as the number itself being even
Highest set bitbit 16worth 65,536
Lowest set bitbit 33 trailing zeros
Power of twoNo
Bytes301 db 78
Gray code10011011011000100n XOR (n >> 1); successive values differ in exactly one bit
At each machine width
32-bit00000000000000011101101101111000
64-bit0000000000000000000000000000000000000000000000011101101101111000
One's complement11111111111111100010010010000111at 32 bits, every bit flipped
Bits reversed00011110110110111000000000000000at 32 bits
Rotated left by 100000000000000111011011011110000at 32 bits, wrapping
Shifted left by 1111011011011110000= 243,440, no wrap
Shifted right by 11110110110111100= 60,860, discarding the low bit
These bits as a double6.01376704 × 10^-319≈IEEE-754 binary64 reinterpretation of the same 64 bits (subnormal)
Nearest landmarks
Powers & multiples
121,720 to the power 214,815,758,400
121,720 to the power 31,803,374,112,448,000
121,720 to the power 4219,506,696,967,170,560,000
121,720 to the power 526,718,355,154,844,000,563,200,000
First ten multiples121,720, 243,440, 365,160, 486,880, 608,600, 730,320, 852,040, 973,760, 1,095,480, 1,217,200
Powers of twoBetween 2^16 (65,536) and 2^17 (131,072)
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 4
Divisible by 8Yes
Divisible by 9No, remainder 4
Divisible by 10Yes
Divisible by 11No, remainder 5
Divisible by 12No, remainder 4
Divisible by 100No, remainder 20
Collatz (3n + 1) trajectory
Steps to reach 1118the total stopping time
Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven
First steps121,720 → 60,860 → 30,430 → 15,215 → 45,646 → 22,823 → 68,470 → 34,235 → 102,706 → 51,353 → …
Last steps… → 5 → 16 → 8 → 4 → 2 → 1
As a percentage & fraction
As a percentage12,172,000%
121,720% as a decimal1,217.2
121,720% of 100121,720
121,720% of 1,0001,217,200
As a fraction of 100121,720/100
Read another way
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Derived from 121,720
Also reads as
#121720 (colour)
- #121720
- Blue
- Dark
- Nearest: Black
#121720 is a blue with RGB values 18, 23, 32 and HSL 219°, 28%, 10%. It is a dark colour, so white text on it reaches 18:1 contrast (AAA for normal text). The nearest named colour is Black.
Colour values
#121720#121720
HEX#121720
RGBrgb(18, 23, 32)
RGB (0–1)0.0706, 0.0902, 0.1255
RGB percentages7.1%, 9%, 12.5%
HSLhsl(218.6, 28%, 9.8%)
HSV / HSBhsv(218.6, 43.8%, 12.5%)
CMYK43.8%, 28.1%, 0%, 87.5%≈naive device-independent conversion; real print needs an ICC profile
24-bit integer1,185,568
CSS custom property--colour: #121720;
Brightness & contrast
Relative luminance0.00846WCAG 2.x, 0 is black and 1 is white
Perceived brightness22.9 of 255ITU-R BT.601 weighting
Light or darkDark
Best text colour on this backgroundWhitecontrast 17.96:1
Contrast with white17.96:1WCAG normal text: AAA
Contrast with black1.17:1WCAG normal text: Fail
Greyscale equivalent#171717
Inverted#EDE8DF
Colour vision & accessibility
Distinguishable without hueYesnever rely on hue alone to carry meaning
Contrast with white, large text17.96:1WCAG large text: AAA
Contrast with black, large text1.17:1WCAG large text: Fail
Named colours
Hue familyblue
CSS keyword usableNo exact keyword
Colour harmonies
Complementary#201B12
Analogous#121E20, #141220
Triadic#201217, #172012
Split complementary#201412, #1E2012
Tetradic#20121E, #201B12, #122014
Tints, shades & saturation
Channel breakdown
R18
G23
B32
Red18 (7.1%)
Green23 (9%)
Blue32 (12.5%)
Hue218.57°
Saturation (HSL)28%
Lightness9.8%
Dominant channelBlue
Hex per channelR 12 · G 17 · B 20
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Harmonies
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