Live analysis

21,120

21,120 is a composite number, even.

This number doesn't have a permanent NumberWiki page yet — what you see below is computed live. Pages get added to the permanent index when they're notable (years, primes, curated, etc.).

21,120 (twenty-one thousand one hundred twenty) is an even 5-digit number. It is a composite number with 64 divisors, and factors as 2⁷ × 3 × 5 × 11. Its proper divisors sum to 52,320, more than the number itself, making it an abundant number. Written other ways, in hexadecimal, 0x5280.

Abundant Number Evil Number Gapful Number Happy Number Harshad / Niven Practical Number Recamán's Sequence Refactorable Number Semiperfect Number

Interestingness

★ ★ ★ ★ ☆

7 notable facts · grade B

21,108 21,109 21,110 21,111 21,112 21,113 21,114 21,115 21,116 21,117 21,118 21,119 21,120 21,121 21,122 21,123 21,124 21,125 21,126 21,127 21,128 21,129 21,130 21,131 21,132

less more

Properties

Parity: Even
Digit count: 5
Digit sum: 6
Digit product: 0
Digital root: 6
Palindrome: No
Bit width: 15 bits
Reversed: 2,112
Recamán's sequence: a(41,599) = 21,120
Square (n²): 446,054,400
Cube (n³): 9,420,668,928,000
Divisor count: 64
σ(n) — sum of divisors: 73,440
φ(n) — Euler's totient: 5,120
Sum of prime factors: 33

Primality

Prime factorization: 2 ⁷ × 3 × 5 × 11

Nearest primes: 21,107 (−13) · 21,121 (+1)

Divisors & multiples

All divisors (64)

1 · 2 · 3 · 4 · 5 · 6 · 8 · 10 · 11 · 12 · 15 · 16 · 20 · 22 · 24 · 30 · 32 · 33 · 40 · 44 · 48 · 55 · 60 · 64 · 66 · 80 · 88 · 96 · 110 · 120 · 128 · 132 · 160 · 165 · 176 · 192 · 220 · 240 · 264 · 320 · 330 · 352 · 384 · 440 · 480 · 528 · 640 · 660 · 704 · 880 · 960 · 1056 · 1320 · 1408 · 1760 · 1920 · 2112 · 2640 · 3520 · 4224 · 5280 · 7040 · 10560 (half) · 21120

Aliquot sum (sum of proper divisors): 52,320

Factor pairs (a × b = 21,120)

1 × 21120

2 × 10560

3 × 7040

4 × 5280

5 × 4224

6 × 3520

8 × 2640

10 × 2112

11 × 1920

12 × 1760

15 × 1408

16 × 1320

20 × 1056

22 × 960

24 × 880

30 × 704

32 × 660

33 × 640

40 × 528

44 × 480

48 × 440

55 × 384

60 × 352

64 × 330

66 × 320

80 × 264

88 × 240

96 × 220

110 × 192

120 × 176

128 × 165

132 × 160

First multiples

21,120 · 42,240 (double) · 63,360 · 84,480 · 105,600 · 126,720 · 147,840 · 168,960 · 190,080 · 211,200

Sums & aliquot sequence

As consecutive integers: 7,039 + 7,040 + 7,041 4,222 + 4,223 + 4,224 + 4,225 + 4,226 1,915 + 1,916 + … + 1,925 1,401 + 1,402 + … + 1,415

Aliquot sequence: 21,120 → 52,320 → 114,000 → 272,880 → 645,960 → 1,571,640 → 3,819,720 → 7,772,280 → 15,728,520 → 31,457,400 → 77,389,800 → 162,520,440 → 325,041,240 → 651,766,920 → 1,600,300,920 → 3,200,602,200 → 6,721,266,480 — unresolved within range

Continued fraction of √n

√21,120 = [145; (3, 17, 1, 4, 1, 71, 1, 4, 1, 17, 3, 290)]

Period length 12 — the block in parentheses repeats forever.

Representations

In words: twenty-one thousand one hundred twenty
Ordinal: 21120th
Binary: 101001010000000
Octal: 51200
Hexadecimal: 0x5280
Base64: UoA=
One's complement: 44,415 (16-bit)
Scientific notation: 2.112 × 10⁴
As a duration: 21,120 s = 5 hours, 52 minutes

In other bases

ternary (3) 1001222020

quaternary (4) 11022000

quinary (5) 1133440

senary (6) 241440

septenary (7) 115401

nonary (9) 31866

undecimal (11) 14960

duodecimal (12) 10280

tridecimal (13) 97c8

tetradecimal (14) 79a8

pentadecimal (15) 63d0

As an angle

21,120° = 58 × 360° + 240°

240° ≈ 4.189 rad

Compass bearing: WSW (west-southwest)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹 ·
Egyptian hieroglyphic: 𓂍𓂍𓆼𓍢𓎆𓎆
Greek (Milesian): ͵καρκʹ
Mayan (base 20): 𝋢·𝋬·𝋰·𝋠
Chinese: 二萬一千一百二十
Chinese (financial): 貳萬壹仟壹佰貳拾

In other modern scripts

Eastern Arabic ٢١١٢٠ Devanagari २११२० Bengali ২১১২০ Tamil ௨௧௧௨௦ Thai ๒๑๑๒๐ Tibetan ༢༡༡༢༠ Khmer ២១១២០ Lao ໒໑໑໒໐ Burmese ၂၁၁၂၀

Digit at this position in famous constants

π — Pi (π): Digit 21,120 = 8
e — Euler's number (e): Digit 21,120 = 1
φ — Golden ratio (φ): Digit 21,120 = 2
√2 — Pythagoras's (√2): Digit 21,120 = 6
ln 2 — Natural log of 2: Digit 21,120 = 3
γ — Euler-Mascheroni (γ): Digit 21,120 = 7

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21120, here are decompositions:

13 + 21107 = 21120
19 + 21101 = 21120
31 + 21089 = 21120
53 + 21067 = 21120
59 + 21061 = 21120
61 + 21059 = 21120
89 + 21031 = 21120
97 + 21023 = 21120

Showing the first eight; more decompositions exist.

Unicode codepoint

劀

CJK Unified Ideograph-5280

U+5280

Other letter (Lo)

UTF-8 encoding: E5 8A 80 (3 bytes).

Lookup U+5280 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#005280

RGB(0, 82, 128)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.128.

Address: 0.0.82.128
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.82.128

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

Position in π

The digit sequence 21120 first appears in π at position 3,821 of the decimal expansion (the 3,821ordinal-suffix:st 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.

Look up 21120 on Pi Search ↗