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Number

21,859

21,859 is a prime, odd.

21,859 (twenty-one thousand eight hundred fifty-nine) is an odd 5-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in hexadecimal, 0x5563.

Arithmetic Number Cousin Prime Cube-Free Deficient Number Evil Number Prime Recamán's Sequence Squarefree

Interestingness

Properties

Parity
Odd
Digit count
5
Digit sum
25
Digit product
720
Digital root
7
Palindrome
No
Bit width
15 bits
Reversed
95,812
Recamán's sequence
a(168,045) = 21,859
Square (n²)
477,815,881
Cube (n³)
10,444,577,342,779
Divisor count
2
σ(n) — sum of divisors
21,860
φ(n) — Euler's totient
21,858

Primality

21,859 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)
1 · 21859
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 21,859)
1 × 21859
First multiples
21,859 · 43,718 (double) · 65,577 · 87,436 · 109,295 · 131,154 · 153,013 · 174,872 · 196,731 · 218,590

Sums & aliquot sequence

As consecutive integers: 10,929 + 10,930

Continued fraction of √n

√21,859 = [147; (1, 5, 1, 1, 2, 1, 6, 6, 3, 1, 1, 2, 1, 1, 1, 1, 2, 1, 18, 1, 97, 1, 1, 1, …)]

Representations

In words
twenty-one thousand eight hundred fifty-nine
Ordinal
21859th
Binary
101010101100011
Octal
52543
Hexadecimal
0x5563
Base64
VWM=
One's complement
43,676 (16-bit)
Scientific notation
2.1859 × 10⁴
As a duration
21,859 s = 6 hours, 4 minutes, 19 seconds
In other bases
ternary (3) 1002222121
quaternary (4) 11111203
quinary (5) 1144414
senary (6) 245111
septenary (7) 120505
nonary (9) 32877
undecimal (11) 15472
duodecimal (12) 10797
tridecimal (13) 9c46
tetradecimal (14) 7d75
pentadecimal (15) 6724

As an angle

21,859° = 60 × 360° + 259°
259° ≈ 4.52 rad
Compass bearing: W (west)

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹𒁹 𒁹𒁹𒁹𒁹 𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian)
͵καωνθʹ
Mayan (base 20)
𝋢·𝋮·𝋬·𝋳
Chinese
二萬一千八百五十九
Chinese (financial)
貳萬壹仟捌佰伍拾玖
In other modern scripts
Eastern Arabic ٢١٨٥٩ Devanagari २१८५९ Bengali ২১৮৫৯ Tamil ௨௧௮௫௯ Thai ๒๑๘๕๙ Tibetan ༢༡༨༥༩ Khmer ២១៨៥៩ Lao ໒໑໘໕໙ Burmese ၂၁၈၅၉

Digit at this position in famous constants

π — Pi (π)
Digit 21,859 = 3
e — Euler's number (e)
Digit 21,859 = 1
φ — Golden ratio (φ)
Digit 21,859 = 6
√2 — Pythagoras's (√2)
Digit 21,859 = 3
ln 2 — Natural log of 2
Digit 21,859 = 2
γ — Euler-Mascheroni (γ)
Digit 21,859 = 9

Also seen as

Prime neighborhood

Adjacent primes:

  • Previous prime: 21,851 (gap of 8)
  • Next prime: 21,863 (gap of 4)

Pair status: cousin with 21863.

Unicode codepoint
CJK Unified Ideograph-5563
U+5563
Other letter (Lo)

UTF-8 encoding: E5 95 A3 (3 bytes).

Hex color
#005563
RGB(0, 85, 99)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.85.99.

Address
0.0.85.99
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.85.99

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

Position in π

The digit sequence 21859 first appears in π at position 53,332 of the decimal expansion (the 53,332ordinal-suffix:nd 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.
  • Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.