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Number

21,013

21,013 is a prime, odd.

Arithmetic Number Cousin Prime Deficient Number Evil Number Prime Pythagorean Prime Recamán's Sequence Sexy Prime Squarefree Twin Prime

Properties

Parity
Odd
Digit count
5
Digit sum
7
Digit product
0
Digital root
7
Palindrome
No
Bit width
15 bits
Reversed
31,012
Recamán's sequence
a(41,813) = 21,013
Square (n²)
441,546,169
Cube (n³)
9,278,209,649,197
Divisor count
2
σ(n) — sum of divisors
21,014
φ(n) — Euler's totient
21,012

Primality

21,013 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)
1 · 21013
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 21,013)
1 × 21013
First multiples
21,013 · 42,026 (double) · 63,039 · 84,052 · 105,065 · 126,078 · 147,091 · 168,104 · 189,117 · 210,130

Sums & aliquot sequence

As a sum of two squares: 102² + 103²
As consecutive integers: 10,506 + 10,507

Representations

In words
twenty-one thousand thirteen
Ordinal
21013th
Binary
101001000010101
Octal
51025
Hexadecimal
0x5215
Base64
UhU=
One's complement
44,522 (16-bit)
In other bases
ternary (3) 1001211021
quaternary (4) 11020111
quinary (5) 1133023
senary (6) 241141
septenary (7) 115156
nonary (9) 31737
undecimal (11) 14873
duodecimal (12) 101b1
tridecimal (13) 9745
tetradecimal (14) 792d
pentadecimal (15) 635d

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋 𒌋𒁹𒁹𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓎆𓏺𓏺𓏺
Greek (Milesian)
͵καιγʹ
Mayan (base 20)
𝋢·𝋬·𝋪·𝋭
Chinese
二萬一千零一十三
Chinese (financial)
貳萬壹仟零壹拾參
In other modern scripts
Eastern Arabic ٢١٠١٣ Devanagari २१०१३ Bengali ২১০১৩ Tamil ௨௧௦௧௩ Thai ๒๑๐๑๓ Tibetan ༢༡༠༡༣ Khmer ២១០១៣ Lao ໒໑໐໑໓ Burmese ၂၁၀၁၃

Digit at this position in famous constants

π — Pi (π)
Digit 21,013 = 5
e — Euler's number (e)
Digit 21,013 = 9
φ — Golden ratio (φ)
Digit 21,013 = 5
√2 — Pythagoras's (√2)
Digit 21,013 = 0
ln 2 — Natural log of 2
Digit 21,013 = 1
γ — Euler-Mascheroni (γ)
Digit 21,013 = 8

Also seen as

Prime neighborhood

Adjacent primes:

  • Previous prime: 21,011 (gap of 2)
  • Next prime: 21,017 (gap of 4)

Pair status: twin with 21011, cousin with 21017.

Unicode codepoint
CJK Unified Ideograph-5215
U+5215
Other letter (Lo)

UTF-8 encoding: E5 88 95 (3 bytes).

Hex color
#005215
RGB(0, 82, 21)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.21.

Address
0.0.82.21
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.82.21

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

Position in π

The digit sequence 21013 first appears in π at position 321,292 of the decimal expansion (the 321,292ordinal-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.