6,991
6,991 is a prime, odd.
6,991 (six thousand nine hundred ninety-one) is an odd 4-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in hexadecimal, 0x1B4F.
Interestingness
Properties
- Parity
- Odd
- Digit count
- 4
- Digit sum
- 25
- Digit product
- 486
- Digital root
- 7
- Palindrome
- No
- Bit width
- 13 bits
- Reversed
- 1,996
- Flips to (rotate 180°)
- 1,669
- Recamán's sequence
- a(177,029) = 6,991
- Square (n²)
- 48,874,081
- Cube (n³)
- 341,678,700,271
- Divisor count
- 2
- σ(n) — sum of divisors
- 6,992
- φ(n) — Euler's totient
- 6,990
Primality
6,991 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√6,991 = [83; (1, 1, 1, 1, 2, 1, 2, 8, 1, 11, 1, 32, 1, 1, 10, 1, 1, 1, 3, 1, 1, 1, 2, 2, …)]
Representations
- In words
- six thousand nine hundred ninety-one
- Ordinal
- 6991st
- Binary
- 1101101001111
- Octal
- 15517
- Hexadecimal
- 0x1B4F
- Base64
- G08=
- One's complement
- 58,544 (16-bit)
- Scientific notation
- 6.991 × 10³
- As a duration
- 6,991 s = 1 hour, 56 minutes, 31 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒁹
- Egyptian hieroglyphic
- 𓆼𓆼𓆼𓆼𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺
- Greek (Milesian)
- ͵ϛϡϟαʹ
- Mayan (base 20)
- 𝋱·𝋩·𝋫
- Chinese
- 六千九百九十一
- Chinese (financial)
- 陸仟玖佰玖拾壹
Digit at this position in famous constants
- π — Pi (π)
- Digit 6,991 = 2
- e — Euler's number (e)
- Digit 6,991 = 3
- φ — Golden ratio (φ)
- Digit 6,991 = 5
- √2 — Pythagoras's (√2)
- Digit 6,991 = 9
- ln 2 — Natural log of 2
- Digit 6,991 = 3
- γ — Euler-Mascheroni (γ)
- Digit 6,991 = 6
Also seen as
UTF-8 encoding: E1 AD 8F (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.27.79.
- Address
- 0.0.27.79
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.27.79
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Heard as a frequency, 6,991 Hz is closest to:
- Concert pitch (A4 = 440 Hz): A8 (7040 Hz, -12¢)
- Scientific pitch (C4 = 256 Hz): A8 (6888.6 Hz, +26¢)
- Baroque pitch (A4 = 415 Hz): A♯8 (7034.8 Hz, -11¢)
The digit sequence 6991 first appears in π at position 10,760 of the decimal expansion (the 10,760ordinal-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.
Related reading
- Prime numbers — The building blocks of arithmetic: what primes are, why they matter, and how we find them.
- Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.