Number

24

24 is a composite number, even, a calendar year.

24 (twenty-four) is an even 2-digit number. It is a composite number with 8 divisors, and factors as 2³ × 3. Its proper divisors sum to 36, more than the number itself, making it an abundant number. It is a factorial (4! = 24). Written other ways, in Roman numerals it is XXIV and in binary, 11000.

Abundant Number Evil Number Factorial Harshad / Niven Highly Abundant Highly Composite Number Nonagonal Pernicious Number Practical Number Preferred Number Recamán's Sequence Refactorable Number Semiperfect Number Tribonacci Number Year Zuckerman Number

Interestingness

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12 notable facts · grade A

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Historical context — 24 AD

Calendar year

AD 24 (XXIV) was a leap year starting on Saturday of the Julian calendar.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 Read the full article on Wikipedia →

Historical context — 24 BC

Calendar year

Year 24 BC was either a common year starting on Thursday, Friday or Saturday or a leap year starting on Friday of the Julian calendar and a common year starting on Thursday of the Proleptic Julian calendar.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 Read the full article on Wikipedia →

Year facts

Year type: Leap year
Divisible by 4 and not by 100; February has 29 days.
Days in year: 366
ISO weeks: 52
Started on: Monday
January 1, 24
Ended on: Tuesday
December 31, 24
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 20s
20–29
Century: 1st century
1–100
Millennium: 1st millennium
1–1000
Years ago: 2,002
2002 years before 2026.

In other calendars

Hebrew: 3784 / 3785 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Wood zodiac:Monkey
Sexagenary cycle position 21 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 567 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 16 / 17 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): -54 / -55 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 2
Digit sum: 6
Digit product: 8
Digital root: 6
Palindrome: No
Bit width: 5 bits
Reversed: 42
Recamán's sequence: a(15) = 24
Square (n²): 576
Cube (n³): 13,824
Divisor count: 8
σ(n) — sum of divisors: 60
φ(n) — Euler's totient: 8
Sum of prime factors: 9

Primality

Prime factorization: 2 ³ × 3

Nearest primes: 23 (−1) · 29 (+5)

Divisors & multiples

All divisors (8)

1 · 2 · 3 · 4 · 6 · 8 · 12 (half) · 24

Aliquot sum (sum of proper divisors): 36

Factor pairs (a × b = 24)

1 × 24

2 × 12

3 × 8

4 × 6

First multiples

24 · 48 (double) · 72 · 96 · 120 · 144 · 168 · 192 · 216 · 240

Sums & aliquot sequence

As consecutive integers: 7 + 8 + 9

Aliquot sequence: 24 → 36 → 55 → 17 → 1 → 0 — terminates at zero

Continued fraction of √n

√24 = [4; (1, 8)]

Period length 2 — the block in parentheses repeats forever.

Representations

In words: twenty-four
Ordinal: 24th
Roman numeral: XXIV
Binary: 11000
Octal: 30
Hexadecimal: 0x18
Base64: GA==
One's complement: 231 (8-bit)
Scientific notation: 2.4 × 10¹

In other bases

ternary (3) 220

quaternary (4) 120

quinary (5) 44

senary (6) 40

septenary (7) 33

nonary (9) 26

undecimal (11) 22

duodecimal (12) 20

tridecimal (13) 1b

tetradecimal (14) 1a

pentadecimal (15) 19

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓎆𓎆𓏺𓏺𓏺𓏺
Greek (Milesian): κδʹ
Mayan (base 20): 𝋡·𝋤
Chinese: 二十四
Chinese (financial): 貳拾肆

In other modern scripts

Eastern Arabic ٢٤ Devanagari २४ Bengali ২৪ Tamil ௨௪ Thai ๒๔ Tibetan ༢༤ Khmer ២៤ Lao ໒໔ Burmese ၂၄

Digit at this position in famous constants

π — Pi (π): Digit 24 = 4
e — Euler's number (e): Digit 24 = 8
φ — Golden ratio (φ): Digit 24 = 8
√2 — Pythagoras's (√2): Digit 24 = 8
ln 2 — Natural log of 2: Digit 24 = 3
γ — Euler-Mascheroni (γ): Digit 24 = 1

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 24, here are decompositions:

5 + 19 = 24
7 + 17 = 24
11 + 13 = 24

ASCII character

As an ASCII codepoint, 24 is control character (0x18). ASCII control character.

Hex color

#000018

RGB(0, 0, 24)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.24.

Address: 0.0.0.24
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.24

Unspecified address (0.0.0.0/8) — "this network" placeholder.

US numbered highway

Matches numbered highway designation:

I-24 — Pulley's Mill, IL to Chattanooga, TN.

Interstate 24 on Wikipedia ↗

Musical pitch

Heard as a frequency, 24 Hz is closest to:

Concert pitch (A4 = 440 Hz): G0 (24.5 Hz, -36¢)
Scientific pitch (C4 = 256 Hz): G0 (24 Hz, +2¢)
Baroque pitch (A4 = 415 Hz): G♯0 (24.5 Hz, -34¢)

(very low — many laptop and phone speakers can't reproduce it)

As a MIDI note number, 24 is C1 (32.7 Hz at concert pitch). (very low — many laptop and phone speakers can't reproduce it)

Atomic number

On the periodic table, atomic number 24 is Chromium (Cr) — period 4.

Chromium on Wikipedia ↗

Time & calendar

24 is the number of hours in a day.

Units of time — Wikipedia ↗