Number

31,121

31,121 is a prime, odd.

31,121 (thirty-one thousand one hundred twenty-one) is an odd 5-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in hexadecimal, 0x7991.

Arithmetic Number Chen Prime Cube-Free Deficient Number Emirp Evil Number Prime Pythagorean Prime Recamán's Sequence Squarefree Twin Prime

Interestingness

★ ★ ★ ★ ★

9 notable facts · grade A

31,109 31,110 31,111 31,112 31,113 31,114 31,115 31,116 31,117 31,118 31,119 31,120 31,121 31,122 31,123 31,124 31,125 31,126 31,127 31,128 31,129 31,130 31,131 31,132 31,133

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Properties

Parity: Odd
Digit count: 5
Digit sum: 8
Digit product: 6
Digital root: 8
Palindrome: No
Bit width: 15 bits
Reversed: 12,113
Recamán's sequence: a(31,421) = 31,121
Square (n²): 968,516,641
Cube (n³): 30,141,206,384,561
Divisor count: 2
σ(n) — sum of divisors: 31,122
φ(n) — Euler's totient: 31,120

Primality

31,121 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)

1 · 31121

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 31,121)

1 × 31121

First multiples

31,121 · 62,242 (double) · 93,363 · 124,484 · 155,605 · 186,726 · 217,847 · 248,968 · 280,089 · 311,210

Sums & aliquot sequence

As a sum of two squares: 65² + 164²

As consecutive integers: 15,560 + 15,561

Continued fraction of √n

√31,121 = [176; (2, 2, 3, 10, 1, 2, 1, 2, 1, 1, 1, 5, 2, 1, 8, 7, 2, 1, 1, 4, 4, 5, 5, 4, …)]

Period length 45 — the block in parentheses repeats forever.

Representations

In words: thirty-one thousand one hundred twenty-one
Ordinal: 31121st
Binary: 111100110010001
Octal: 74621
Hexadecimal: 0x7991
Base64: eZE=
One's complement: 34,414 (16-bit)
Scientific notation: 3.1121 × 10⁴
As a duration: 31,121 s = 8 hours, 38 minutes, 41 seconds

In other bases

ternary (3) 1120200122

quaternary (4) 13212101

quinary (5) 1443441

senary (6) 400025

septenary (7) 156506

nonary (9) 46618

undecimal (11) 21422

duodecimal (12) 16015

tridecimal (13) 1121c

tetradecimal (14) b4ad

pentadecimal (15) 934b

Palindromic in base 5

As an angle

31,121° = 86 × 360° + 161°

161° ≈ 2.81 rad

Compass bearing: SSE (south-southeast)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹
Egyptian hieroglyphic: 𓂍𓂍𓂍𓆼𓍢𓎆𓎆𓏺
Greek (Milesian): ͵λαρκαʹ
Mayan (base 20): 𝋣·𝋱·𝋰·𝋡
Chinese: 三萬一千一百二十一
Chinese (financial): 參萬壹仟壹佰貳拾壹

In other modern scripts

Eastern Arabic ٣١١٢١ Devanagari ३११२१ Bengali ৩১১২১ Tamil ௩௧௧௨௧ Thai ๓๑๑๒๑ Tibetan ༣༡༡༢༡ Khmer ៣១១២១ Lao ໓໑໑໒໑ Burmese ၃၁၁၂၁

Digit at this position in famous constants

π — Pi (π): Digit 31,121 = 6
e — Euler's number (e): Digit 31,121 = 9
φ — Golden ratio (φ): Digit 31,121 = 2
√2 — Pythagoras's (√2): Digit 31,121 = 3
ln 2 — Natural log of 2: Digit 31,121 = 3
γ — Euler-Mascheroni (γ): Digit 31,121 = 9

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 31,091 (gap of 30)
Next prime: 31,123 (gap of 2)

Pair status: twin with 31123.

Unicode codepoint

禑

CJK Unified Ideograph-7991

U+7991

Other letter (Lo)

UTF-8 encoding: E7 A6 91 (3 bytes).

Lookup U+7991 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#007991

RGB(0, 121, 145)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.121.145.

Address: 0.0.121.145
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.121.145

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

Position in π

The digit sequence 31121 first appears in π at position 38,338 of the decimal expansion (the 38,338ordinal-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.

Look up 31121 on Pi Search ↗