Number
21,121
21,121 is a prime, odd.
Properties
- Parity
- Odd
- Digit count
- 5
- Digit sum
- 7
- Digit product
- 4
- Digital root
- 7
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 12,112
- Recamán's sequence
- a(41,597) = 21,121
- Square (n²)
- 446,096,641
- Cube (n³)
- 9,422,007,154,561
- Divisor count
- 2
- σ(n) — sum of divisors
- 21,122
- φ(n) — Euler's totient
- 21,120
Primality
21,121 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Aliquot sum (sum of proper divisors):
1
First multiples
21,121
·
42,242
(double)
·
63,363
·
84,484
·
105,605
·
126,726
·
147,847
·
168,968
·
190,089
·
211,210
Sums & aliquot sequence
As a sum of two squares:
39² + 140²
As consecutive integers:
10,560 + 10,561
Representations
- In words
- twenty-one thousand one hundred twenty-one
- Ordinal
- 21121st
- Binary
- 101001010000001
- Octal
- 51201
- Hexadecimal
- 0x5281
- Base64
- UoE=
- One's complement
- 44,414 (16-bit)
In other bases
ternary (3)
1001222021
quaternary (4)
11022001
quinary (5)
1133441
senary (6)
241441
septenary (7)
115402
nonary (9)
31867
undecimal (11)
14961
duodecimal (12)
10281
tridecimal (13)
97c9
tetradecimal (14)
79a9
pentadecimal (15)
63d1
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹 𒁹
- Egyptian hieroglyphic
- 𓂍𓂍𓆼𓍢𓎆𓎆𓏺
- Greek (Milesian)
- ͵καρκαʹ
- Mayan (base 20)
- 𝋢·𝋬·𝋰·𝋡
- Chinese
- 二萬一千一百二十一
- Chinese (financial)
- 貳萬壹仟壹佰貳拾壹
In other modern scripts
Eastern Arabic
٢١١٢١
Devanagari
२११२१
Bengali
২১১২১
Tamil
௨௧௧௨௧
Thai
๒๑๑๒๑
Tibetan
༢༡༡༢༡
Khmer
២១១២១
Lao
໒໑໑໒໑
Burmese
၂၁၁၂၁
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,121 = 7
- e — Euler's number (e)
- Digit 21,121 = 4
- φ — Golden ratio (φ)
- Digit 21,121 = 9
- √2 — Pythagoras's (√2)
- Digit 21,121 = 8
- ln 2 — Natural log of 2
- Digit 21,121 = 5
- γ — Euler-Mascheroni (γ)
- Digit 21,121 = 0
Also seen as
Unicode codepoint
劁
CJK Unified Ideograph-5281
U+5281
Other letter (Lo)
UTF-8 encoding: E5 8A 81 (3 bytes).
Hex color
#005281
RGB(0, 82, 129)
IPv4 address
As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.129.
- Address
- 0.0.82.129
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.82.129
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Position in π
The digit sequence 21121 first appears in π at position 68,809 of the decimal expansion (the 68,809ordinal-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.