Number
720
- Positive
- Even
- Composite
- 3 digits
720 is an even 3-digit integer and a composite number. It has 30 divisors and a digital root of 9.
Number properties
ParityEvendivisible by 2
SignPositive
PrimalityComposite
Absolute value720
Digit count3
Digit sum9
Digital root9repeated digit sum
PalindromicNoreads differently backwards
Happy numberNosquared-digit sums reach 1
Harshad numberYesdivisible by its own digit sum
Factors & divisors
Prime factorisation2^4 × 3^2 × 5
Distinct prime factors32, 3, 5
Number of divisors30
Sum of divisors σ(n)2,418
Aliquot sum1,698sum of the proper divisors
ClassificationAbundantthe aliquot sum exceeds the number
Euler's totient φ(n)192integers below n that share no factor with it
SquarefreeNohas a repeated prime factor
All divisors1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 30, 36, 40, 45, 48, 60, 72, 80, 90, 120, 144, 180, 240, 360, 72030 in total
Arithmetic
Representations
Decimal720
Binary101101000010 bits
Octal1320
Hexadecimal2D0
Base 36K0
Roman numeralDCCXX
In wordsseven hundred and twenty
Ordinalseven hundred and twentieth
Scientific notation7.2 × 10^2
Engineering notation720
Nearest landmarks
Powers & multiples
720 to the power 2518,400
720 to the power 3373,248,000
720 to the power 4268,738,560,000
720 to the power 5193,491,763,200,000
First ten multiples720, 1,440, 2,160, 2,880, 3,600, 4,320, 5,040, 5,760, 6,480, 7,200
Powers of twoBetween 2^9 (512) and 2^10 (1,024)
Divisibility tests
Divisible by 2Yes
Divisible by 3Yes
Divisible by 4Yes
Divisible by 5Yes
Divisible by 6Yes
Divisible by 7No, remainder 6
Divisible by 8Yes
Divisible by 9Yes
Divisible by 10Yes
Divisible by 11No, remainder 5
Divisible by 12Yes
Divisible by 100No, remainder 20
Collatz (3n + 1) trajectory
Steps to reach 120the total stopping time
Highest value reached720
Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven
First steps720 → 360 → 180 → 90 → 45 → 136 → 68 → 34 → 17 → 52 → …
Last steps… → 5 → 16 → 8 → 4 → 2 → 1
As a percentage & fraction
As a percentage72,000%
720% as a decimal7.2
720% of 100720
720% of 1,0007,200
As a fraction of 100720/100
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Derived from 720
Other readings
Also reads as
#772200 (colour)
- #772200
- Orange
- Dark
- Nearest: Maroon
#772200 is a orange with RGB values 119, 34, 0 and HSL 17°, 100%, 23%. It is a dark colour, so white text on it reaches 10.4:1 contrast (AAA for normal text). The nearest named colour is Maroon.
Colour values
#772200#772200
HEX#772200
HEX (short)#720
RGBrgb(119, 34, 0)
RGB (0–1)0.4667, 0.1333, 0
RGB percentages46.7%, 13.3%, 0%
HSLhsl(17.1, 100%, 23.3%)
HSV / HSBhsv(17.1, 100%, 46.7%)
CMYK0%, 71.4%, 100%, 53.3%≈naive device-independent conversion; real print needs an ICC profile
24-bit integer7,807,488
CSS custom property--colour: #772200;
Brightness & contrast
Relative luminance0.05066WCAG 2.x, 0 is black and 1 is white
Perceived brightness70.1 of 255ITU-R BT.601 weighting
Light or darkDark
Best text colour on this backgroundWhitecontrast 10.43:1
Contrast with white10.43:1WCAG normal text: AAA
Contrast with black2.01:1WCAG normal text: Fail
Greyscale equivalent#323232
Inverted#88DDFF
Colour vision & accessibility
Distinguishable without hueShifts in lightness toonever rely on hue alone to carry meaning
Contrast with white, large text10.43:1WCAG large text: AAA
Contrast with black, large text2.01:1WCAG large text: Fail
Named colours
Hue familyorange
CSS keyword usableNo exact keyword
Colour harmonies
Complementary#005577
Analogous#770019, #775D00
Triadic#007722, #220077
Split complementary#00775D, #001A77
Tetradic#1A7700, #005577, #5D0077
Tints, shades & saturation
Channel breakdown
R119
G34
B0
Red119 (46.7%)
Green34 (13.3%)
Blue0 (0%)
Hue17.14°
Saturation (HSL)100%
Lightness23.33%
Dominant channelRed
Hex per channelR 77 · G 22 · B 00
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