Recognised as Number
801
- Positive
- Odd
- Composite
- 3 digits
801 is an odd 3-digit integer and a composite number. It has 6 divisors and a digital root of 9.
Number properties
ParityOddnot divisible by 2
SignPositive
PrimalityComposite
Absolute value801
Digit count3
Digit sum9
Digit product0zero, because one of the digits is zero
Multiplicative persistence1times the digit product can be taken before one digit is left
Digital root9repeated digit sum
PalindromicNoreads differently backwards
Happy numberNosquared-digit sums reach 1
Harshad numberYesdivisible by its own digit sum
Factors & divisors
Prime factorisation3^2 × 89
Distinct prime factors23, 89
Number of divisors6
Sum of divisors σ(n)1,170
Aliquot sum369sum of the proper divisors
ClassificationDeficientthe aliquot sum is less than the number
Euler's totient φ(n)528integers below n that share no factor with it
Carmichael function λ(n)264the smallest exponent with aˣ ≡ 1 for every unit; smaller than φ(n) = 528
Möbius function μ(n)0zero, because a prime divides n twice
SquarefreeNohas a repeated prime factor
All divisors1, 3, 9, 89, 267, 8016 in total
Arithmetic
Representations
Decimal801
Binary110010000110 bits
Octal1441
Hexadecimal321
Base 36M9
Roman numeralDCCCI
In wordseight hundred and one
Ordinaleight hundred and first
Scientific notation8.01 × 10^2
Engineering notation801
In other bases
Ternary1002200base 3; the most digit-efficient integer base after e: 7 digits
Quinary11201base 5; one hand: 5 digits
Septenary2223base 7: 4 digits
Nonary1080base 9; each digit is two ternary digits: 4 digits
Duodecimal569base 12; divides by 2, 3, 4 and 6, which is why eggs and inches come in twelves: 3 digits
Vigesimal201base 20; hands and feet, and the Mayan and Yoruba systems: 3 digits
Sexagesimal13:21base 60; Babylonian, and still how an hour and a circle are divided: 2 digits
Balanced ternary1010T00digits −1, 0 and +1 written T, 0 and 1; negation is swapping T and 1, so no sign is needed
Negabinary11101100001base −2; place values alternate 1, −2, 4, −8, so every integer has exactly one form without a sign
Bit-level
0000001100100001
Bit length10 bitsto write the magnitude
Set bits4the population count, or Hamming weight
Zero bits6within that length
Bit parityeven4 set bits, so even; not the same as the number itself being odd
Highest set bitbit 9worth 512
Lowest set bitbit 00 trailing zeros
Power of twoNo
Bytes203 21
Gray code1010110001n XOR (n >> 1); successive values differ in exactly one bit
At each machine width
16-bit0000001100100001
32-bit00000000000000000000001100100001
64-bit0000000000000000000000000000000000000000000000000000001100100001
One's complement1111110011011110at 16 bits, every bit flipped
Bits reversed1000010011000000at 16 bits
Rotated left by 10000011001000010at 16 bits, wrapping
Shifted left by 111001000010= 1,602, no wrap
Shifted right by 1110010000= 400, discarding the low bit
These bits as a double3.95746582 × 10^-321≈IEEE-754 binary64 reinterpretation of the same 64 bits (subnormal)
Nearest landmarks
Powers & multiples
801 to the power 2641,601
801 to the power 3513,922,401
801 to the power 4411,651,843,201
801 to the power 5329,733,126,404,001
First ten multiples801, 1,602, 2,403, 3,204, 4,005, 4,806, 5,607, 6,408, 7,209, 8,010
Powers of twoBetween 2^9 (512) and 2^10 (1,024)
Divisibility tests
Divisible by 2No, remainder 1
Divisible by 3Yes
Divisible by 4No, remainder 1
Divisible by 5No, remainder 1
Divisible by 6No, remainder 3
Divisible by 7No, remainder 3
Divisible by 8No, remainder 1
Divisible by 9Yes
Divisible by 10No, remainder 1
Divisible by 11No, remainder 9
Divisible by 12No, remainder 9
Divisible by 100No, remainder 1
Collatz (3n + 1) trajectory
Steps to reach 159the total stopping time
Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven
First steps801 → 2,404 → 1,202 → 601 → 1,804 → 902 → 451 → 1,354 → 677 → 2,032 → …
Last steps… → 5 → 16 → 8 → 4 → 2 → 1
As a percentage & fraction
As a percentage80,100%
801% as a decimal8.01
801% of 100801
801% of 1,0008,010
As a fraction of 100801/100
Read another way
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Derived from 801
Other readings
Also reads as
#880011 (colour)
- #880011
- Red
- Dark
- Nearest: Maroon
#880011 is a red with RGB values 136, 0, 17 and HSL 353°, 100%, 27%. It is a dark colour, so white text on it reaches 10.2:1 contrast (AAA for normal text). The nearest named colour is Maroon.
Colour values
#880011#880011
HEX#880011
HEX (short)#801
RGBrgb(136, 0, 17)
RGB (0–1)0.5333, 0, 0.0667
RGB percentages53.3%, 0%, 6.7%
HSLhsl(352.5, 100%, 26.7%)
HSV / HSBhsv(352.5, 100%, 53.3%)
CMYK0%, 100%, 87.5%, 46.7%≈naive device-independent conversion; real print needs an ICC profile
24-bit integer8,912,913
CSS custom property--colour: #880011;
Brightness & contrast
Relative luminance0.05275WCAG 2.x, 0 is black and 1 is white
Perceived brightness74.6 of 255ITU-R BT.601 weighting
Light or darkDark
Best text colour on this backgroundWhitecontrast 10.22:1
Contrast with white10.22:1WCAG normal text: AAA
Contrast with black2.05:1WCAG normal text: Fail
Greyscale equivalent#1E1E1E
Inverted#77FFEE
Colour vision & accessibility
Distinguishable without hueShifts in lightness toonever rely on hue alone to carry meaning
Contrast with white, large text10.22:1WCAG large text: AAA
Contrast with black, large text2.05:1WCAG large text: Fail
Named colours
Hue familyred
CSS keyword usableNo exact keyword
Colour harmonies
Complementary#008877
Analogous#880055, #883300
Triadic#118800, #001188
Split complementary#008833, #005588
Tetradic#558800, #008877, #330088
Tints, shades & saturation
Channel breakdown
R136
G0
B17
Red136 (53.3%)
Green0 (0%)
Blue17 (6.7%)
Hue352.5°
Saturation (HSL)100%
Lightness26.67%
Dominant channelRed
Hex per channelR 88 · G 00 · B 11
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