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Number

21,019

21,019 is a prime, odd.

Arithmetic Number Cousin Prime Deficient Number Odious Number Pernicious Number Prime Recamán's Sequence Sexy Prime Squarefree Twin Prime

Properties

Parity
Odd
Digit count
5
Digit sum
13
Digit product
0
Digital root
4
Palindrome
No
Bit width
15 bits
Reversed
91,012
Recamán's sequence
a(41,801) = 21,019
Square (n²)
441,798,361
Cube (n³)
9,286,159,749,859
Divisor count
2
σ(n) — sum of divisors
21,020
φ(n) — Euler's totient
21,018

Primality

21,019 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)
1 · 21019
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 21,019)
1 × 21019
First multiples
21,019 · 42,038 (double) · 63,057 · 84,076 · 105,095 · 126,114 · 147,133 · 168,152 · 189,171 · 210,190

Sums & aliquot sequence

As consecutive integers: 10,509 + 10,510

Representations

In words
twenty-one thousand nineteen
Ordinal
21019th
Binary
101001000011011
Octal
51033
Hexadecimal
0x521B
Base64
Uhs=
One's complement
44,516 (16-bit)
In other bases
ternary (3) 1001211111
quaternary (4) 11020123
quinary (5) 1133034
senary (6) 241151
septenary (7) 115165
nonary (9) 31744
undecimal (11) 14879
duodecimal (12) 101b7
tridecimal (13) 974b
tetradecimal (14) 7935
pentadecimal (15) 6364

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋 𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian)
͵καιθʹ
Mayan (base 20)
𝋢·𝋬·𝋪·𝋳
Chinese
二萬一千零一十九
Chinese (financial)
貳萬壹仟零壹拾玖
In other modern scripts
Eastern Arabic ٢١٠١٩ Devanagari २१०१९ Bengali ২১০১৯ Tamil ௨௧௦௧௯ Thai ๒๑๐๑๙ Tibetan ༢༡༠༡༩ Khmer ២១០១៩ Lao ໒໑໐໑໙ Burmese ၂၁၀၁၉

Digit at this position in famous constants

π — Pi (π)
Digit 21,019 = 7
e — Euler's number (e)
Digit 21,019 = 4
φ — Golden ratio (φ)
Digit 21,019 = 4
√2 — Pythagoras's (√2)
Digit 21,019 = 8
ln 2 — Natural log of 2
Digit 21,019 = 5
γ — Euler-Mascheroni (γ)
Digit 21,019 = 7

Also seen as

Prime neighborhood

Adjacent primes:

  • Previous prime: 21,017 (gap of 2)
  • Next prime: 21,023 (gap of 4)

Pair status: twin with 21017, cousin with 21023.

Unicode codepoint
CJK Unified Ideograph-521B
U+521B
Other letter (Lo)

UTF-8 encoding: E5 88 9B (3 bytes).

Hex color
#00521B
RGB(0, 82, 27)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.27.

Address
0.0.82.27
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.82.27

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

Position in π

The digit sequence 21019 first appears in π at position 38,858 of the decimal expansion (the 38,858ordinal-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.