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Number

21,383

21,383 is a prime, odd.

21,383 (twenty-one thousand three hundred eighty-three) is an odd 5-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in hexadecimal, 0x5387.

Arithmetic Number Cousin Prime Cube-Free Deficient Number Evil Number Prime Recamán's Sequence Safe Prime Sexy Prime Sophie Germain Prime Squarefree

Interestingness

Properties

Parity
Odd
Digit count
5
Digit sum
17
Digit product
144
Digital root
8
Palindrome
No
Bit width
15 bits
Reversed
38,312
Recamán's sequence
a(41,073) = 21,383
Square (n²)
457,232,689
Cube (n³)
9,777,006,588,887
Divisor count
2
σ(n) — sum of divisors
21,384
φ(n) — Euler's totient
21,382

Primality

21,383 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)
1 · 21383
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 21,383)
1 × 21383
First multiples
21,383 · 42,766 (double) · 64,149 · 85,532 · 106,915 · 128,298 · 149,681 · 171,064 · 192,447 · 213,830

Sums & aliquot sequence

As consecutive integers: 10,691 + 10,692

Continued fraction of √n

√21,383 = [146; (4, 2, 1, 3, 3, 1, 5, 1, 1, 2, 4, 1, 1, 3, 2, 5, 12, 1, 1, 7, 2, 1, 1, 1, …)]

Period length 52 — the block in parentheses repeats forever.

Representations

In words
twenty-one thousand three hundred eighty-three
Ordinal
21383rd
Binary
101001110000111
Octal
51607
Hexadecimal
0x5387
Base64
U4c=
One's complement
44,152 (16-bit)
Scientific notation
2.1383 × 10⁴
As a duration
21,383 s = 5 hours, 56 minutes, 23 seconds
In other bases
ternary (3) 1002022222
quaternary (4) 11032013
quinary (5) 1141013
senary (6) 242555
septenary (7) 116225
nonary (9) 32288
undecimal (11) 1507a
duodecimal (12) 1045b
tridecimal (13) 996b
tetradecimal (14) 7b15
pentadecimal (15) 6508

As an angle

21,383° = 59 × 360° + 143°
143° ≈ 2.496 rad
Compass bearing: SE (southeast)

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒁹𒁹𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺
Greek (Milesian)
͵κατπγʹ
Mayan (base 20)
𝋢·𝋭·𝋩·𝋣
Chinese
二萬一千三百八十三
Chinese (financial)
貳萬壹仟參佰捌拾參
In other modern scripts
Eastern Arabic ٢١٣٨٣ Devanagari २१३८३ Bengali ২১৩৮৩ Tamil ௨௧௩௮௩ Thai ๒๑๓๘๓ Tibetan ༢༡༣༨༣ Khmer ២១៣៨៣ Lao ໒໑໓໘໓ Burmese ၂၁၃၈၃

Digit at this position in famous constants

π — Pi (π)
Digit 21,383 = 8
e — Euler's number (e)
Digit 21,383 = 2
φ — Golden ratio (φ)
Digit 21,383 = 5
√2 — Pythagoras's (√2)
Digit 21,383 = 2
ln 2 — Natural log of 2
Digit 21,383 = 0
γ — Euler-Mascheroni (γ)
Digit 21,383 = 6

Also seen as

Prime neighborhood

Adjacent primes:

  • Previous prime: 21,379 (gap of 4)
  • Next prime: 21,391 (gap of 8)

Pair status: cousin with 21379.

Unicode codepoint
CJK Unified Ideograph-5387
U+5387
Other letter (Lo)

UTF-8 encoding: E5 8E 87 (3 bytes).

Hex color
#005387
RGB(0, 83, 135)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.83.135.

Address
0.0.83.135
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.83.135

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

Position in π

The digit sequence 21383 first appears in π at position 180,704 of the decimal expansion (the 180,704ordinal-suffix:th digit after the integer 3).

Search range: the first 1,000,000 fractional digits of π. Any 6-digit-or-shorter string is virtually guaranteed to appear in there — the more interesting signal is the position.

Related reading

  • Prime numbers — The building blocks of arithmetic: what primes are, why they matter, and how we find them.
  • Mayan numerals — Vigesimal dots-and-bars with a shell zero — one of the earliest true zeros.