Live analysis

2,991

2,991 is a composite number, odd.

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.).

2,991 (two thousand nine hundred ninety-one) is an odd 4-digit number. It is a composite number with 4 divisors, and factors as 3 × 997. Written other ways, in Roman numerals it is MMCMXCI and in binary, 101110101111.

Arithmetic Number Cube-Free Deficient Number Happy Number Odious Number Semiprime Squarefree

Interestingness

★ ★ ★ ☆ ☆

5 notable facts · grade C

2,979 2,980 2,981 2,982 2,983 2,984 2,985 2,986 2,987 2,988 2,989 2,990 2,991 2,992 2,993 2,994 2,995 2,996 2,997 2,998 2,999 3,000 3,001 3,002 3,003

less more

Properties

Parity: Odd
Digit count: 4
Digit sum: 21
Digit product: 162
Digital root: 3
Palindrome: No
Bit width: 12 bits
Reversed: 1,992
Square (n²): 8,946,081
Cube (n³): 26,757,728,271
Divisor count: 4
σ(n) — sum of divisors: 3,992
φ(n) — Euler's totient: 1,992
Sum of prime factors: 1,000

Primality

Prime factorization: 3 × 997

Nearest primes: 2,971 (−20) · 2,999 (+8)

Divisors & multiples

All divisors (4)

1 · 3 · 997 · 2991

Aliquot sum (sum of proper divisors): 1,001

Factor pairs (a × b = 2,991)

1 × 2991

3 × 997

First multiples

2,991 · 5,982 (double) · 8,973 · 11,964 · 14,955 · 17,946 · 20,937 · 23,928 · 26,919 · 29,910

Sums & aliquot sequence

As consecutive integers: 1,495 + 1,496 996 + 997 + 998 496 + 497 + 498 + 499 + 500 + 501

Aliquot sequence: 2,991 → 1,001 → 343 → 57 → 23 → 1 → 0 — terminates at zero

Continued fraction of √n

√2,991 = [54; (1, 2, 4, 2, 2, 1, 2, 10, 1, 1, 3, 8, 7, 1, 2, 4, 36, 4, 2, 1, 7, 8, 3, 1, …)]

Period length 34 — the block in parentheses repeats forever.

Representations

In words: two thousand nine hundred ninety-one
Ordinal: 2991st
Roman numeral: MMCMXCI
Binary: 101110101111
Octal: 5657
Hexadecimal: 0xBAF
Base64: C68=
One's complement: 62,544 (16-bit)
Scientific notation: 2.991 × 10³
As a duration: 2,991 s = 49 minutes, 51 seconds

In other bases

ternary (3) 11002210

quaternary (4) 232233

quinary (5) 43431

senary (6) 21503

septenary (7) 11502

nonary (9) 4083

undecimal (11) 227a

duodecimal (12) 1893

tridecimal (13) 1491

tetradecimal (14) 1139

pentadecimal (15) d46

As an angle

2,991° = 8 × 360° + 111°

111° ≈ 1.937 rad

Compass bearing: ESE (east-southeast)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹
Egyptian hieroglyphic: 𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian): ͵βϡϟαʹ
Mayan (base 20): 𝋧·𝋩·𝋫
Chinese: 二千九百九十一
Chinese (financial): 貳仟玖佰玖拾壹

In other modern scripts

Eastern Arabic ٢٩٩١ Devanagari २९९१ Bengali ২৯৯১ Tamil ௨௯௯௧ Thai ๒๙๙๑ Tibetan ༢༩༩༡ Khmer ២៩៩១ Lao ໒໙໙໑ Burmese ၂၉၉၁

Digit at this position in famous constants

π — Pi (π): Digit 2,991 = 8
e — Euler's number (e): Digit 2,991 = 5
φ — Golden ratio (φ): Digit 2,991 = 1
√2 — Pythagoras's (√2): Digit 2,991 = 1
ln 2 — Natural log of 2: Digit 2,991 = 9
γ — Euler-Mascheroni (γ): Digit 2,991 = 7

Also seen as

Unicode codepoint

ய

Tamil Letter Ya

U+0BAF

Other letter (Lo)

UTF-8 encoding: E0 AE AF (3 bytes).

Lookup U+0BAF on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#000BAF

RGB(0, 11, 175)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.11.175.

Address: 0.0.11.175
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.11.175

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

Musical pitch

Heard as a frequency, 2,991 Hz is closest to:

Concert pitch (A4 = 440 Hz): F♯7 (2960 Hz, +18¢)
Scientific pitch (C4 = 256 Hz): G7 (3068.5 Hz, -44¢)
Baroque pitch (A4 = 415 Hz): G7 (2957.8 Hz, +19¢)

Position in π

The digit sequence 2991 first appears in π at position 6,037 of the decimal expansion (the 6,037ordinal-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 2991 on Pi Search ↗