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Number

12,821

12,821 is a prime, odd.

Arithmetic Number Chen Prime Deficient Number Evil Number Palindrome Prime Pythagorean Prime Recamán's Sequence Sophie Germain Prime Squarefree Twin Prime

Properties

Parity
Odd
Digit count
5
Digit sum
14
Digit product
32
Digital root
5
Palindrome
Yes
Bit width
14 bits
Recamán's sequence
a(48,633) = 12,821
Square (n²)
164,378,041
Cube (n³)
2,107,490,863,661
Divisor count
2
σ(n) — sum of divisors
12,822
φ(n) — Euler's totient
12,820

Primality

12,821 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)
1 · 12821
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 12,821)
1 × 12821
First multiples
12,821 · 25,642 (double) · 38,463 · 51,284 · 64,105 · 76,926 · 89,747 · 102,568 · 115,389 · 128,210

Sums & aliquot sequence

As a sum of two squares: 70² + 89²
As consecutive integers: 6,410 + 6,411

Representations

In words
twelve thousand eight hundred twenty-one
Ordinal
12821st
Binary
11001000010101
Octal
31025
Hexadecimal
0x3215
Base64
MhU=
One's complement
52,714 (16-bit)
In other bases
ternary (3) 122120212
quaternary (4) 3020111
quinary (5) 402241
senary (6) 135205
septenary (7) 52244
nonary (9) 18525
undecimal (11) 96a6
duodecimal (12) 7505
tridecimal (13) 5ab3
tetradecimal (14) 495b
pentadecimal (15) 3beb

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹 𒌋𒌋𒌋𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹
Egyptian hieroglyphic
𓂍𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓏺
Greek (Milesian)
͵ιβωκαʹ
Mayan (base 20)
𝋡·𝋬·𝋡·𝋡
Chinese
一萬二千八百二十一
Chinese (financial)
壹萬貳仟捌佰貳拾壹
In other modern scripts
Eastern Arabic ١٢٨٢١ Devanagari १२८२१ Bengali ১২৮২১ Tamil ௧௨௮௨௧ Thai ๑๒๘๒๑ Tibetan ༡༢༨༢༡ Khmer ១២៨២១ Lao ໑໒໘໒໑ Burmese ၁၂၈၂၁

Digit at this position in famous constants

π — Pi (π)
Digit 12,821 = 2
e — Euler's number (e)
Digit 12,821 = 0
φ — Golden ratio (φ)
Digit 12,821 = 9
√2 — Pythagoras's (√2)
Digit 12,821 = 4
ln 2 — Natural log of 2
Digit 12,821 = 1
γ — Euler-Mascheroni (γ)
Digit 12,821 = 0

Also seen as

Prime neighborhood

Adjacent primes:

  • Previous prime: 12,809 (gap of 12)
  • Next prime: 12,823 (gap of 2)

Pair status: twin with 12823.

Unicode codepoint
Parenthesized Hangul Ieung A
U+3215
Other symbol (So)

UTF-8 encoding: E3 88 95 (3 bytes).

Hex color
#003215
RGB(0, 50, 21)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.50.21.

Address
0.0.50.21
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.50.21

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

Position in π

The digit sequence 12821 first appears in π at position 97,930 of the decimal expansion (the 97,930ordinal-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.