number.wiki
Number

21,011

21,011 is a prime, odd.

Arithmetic Number Chen Prime Deficient Number Evil Number Happy Number Prime Recamán's Sequence Sexy Prime Sophie Germain Prime Squarefree Twin Prime

Properties

Parity
Odd
Digit count
5
Digit sum
5
Digit product
0
Digital root
5
Palindrome
No
Bit width
15 bits
Reversed
11,012
Recamán's sequence
a(41,817) = 21,011
Square (n²)
441,462,121
Cube (n³)
9,275,560,624,331
Divisor count
2
σ(n) — sum of divisors
21,012
φ(n) — Euler's totient
21,010

Primality

21,011 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)
1 · 21011
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 21,011)
1 × 21011
First multiples
21,011 · 42,022 (double) · 63,033 · 84,044 · 105,055 · 126,066 · 147,077 · 168,088 · 189,099 · 210,110

Sums & aliquot sequence

As consecutive integers: 10,505 + 10,506

Representations

In words
twenty-one thousand eleven
Ordinal
21011th
Binary
101001000010011
Octal
51023
Hexadecimal
0x5213
Base64
UhM=
One's complement
44,524 (16-bit)
In other bases
ternary (3) 1001211012
quaternary (4) 11020103
quinary (5) 1133021
senary (6) 241135
septenary (7) 115154
nonary (9) 31735
undecimal (11) 14871
duodecimal (12) 101ab
tridecimal (13) 9743
tetradecimal (14) 792b
pentadecimal (15) 635b

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋 𒌋𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓎆𓏺
Greek (Milesian)
͵καιαʹ
Mayan (base 20)
𝋢·𝋬·𝋪·𝋫
Chinese
二萬一千零一十一
Chinese (financial)
貳萬壹仟零壹拾壹
In other modern scripts
Eastern Arabic ٢١٠١١ Devanagari २१०११ Bengali ২১০১১ Tamil ௨௧௦௧௧ Thai ๒๑๐๑๑ Tibetan ༢༡༠༡༡ Khmer ២១០១១ Lao ໒໑໐໑໑ Burmese ၂၁၀၁၁

Digit at this position in famous constants

π — Pi (π)
Digit 21,011 = 6
e — Euler's number (e)
Digit 21,011 = 8
φ — Golden ratio (φ)
Digit 21,011 = 7
√2 — Pythagoras's (√2)
Digit 21,011 = 4
ln 2 — Natural log of 2
Digit 21,011 = 7
γ — Euler-Mascheroni (γ)
Digit 21,011 = 7

Also seen as

Prime neighborhood

Adjacent primes:

  • Previous prime: 21,001 (gap of 10)
  • Next prime: 21,013 (gap of 2)

Pair status: twin with 21013.

Unicode codepoint
CJK Unified Ideograph-5213
U+5213
Other letter (Lo)

UTF-8 encoding: E5 88 93 (3 bytes).

Hex color
#005213
RGB(0, 82, 19)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.19.

Address
0.0.82.19
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.82.19

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

Position in π

The digit sequence 21011 first appears in π at position 182,680 of the decimal expansion (the 182,680ordinal-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.