18,521
18,521 is a prime, odd.
18,521 (eighteen thousand five 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, 0x4859.
Interestingness
Properties
- Parity
- Odd
- Digit count
- 5
- Digit sum
- 17
- Digit product
- 80
- Digital root
- 8
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 12,581
- Recamán's sequence
- a(9,090) = 18,521
- Square (n²)
- 343,027,441
- Cube (n³)
- 6,353,211,234,761
- Divisor count
- 2
- σ(n) — sum of divisors
- 18,522
- φ(n) — Euler's totient
- 18,520
Primality
18,521 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√18,521 = [136; (10, 1, 7, 1, 1, 2, 11, 2, 3, 1, 1, 2, 2, 54, 54, 2, 2, 1, 1, 3, 2, 11, 2, 1, …)]
Period length 29 — the block in parentheses repeats forever.
Representations
- In words
- eighteen thousand five hundred twenty-one
- Ordinal
- 18521st
- Binary
- 100100001011001
- Octal
- 44131
- Hexadecimal
- 0x4859
- Base64
- SFk=
- One's complement
- 47,014 (16-bit)
- Scientific notation
- 1.8521 × 10⁴
- As a duration
- 18,521 s = 5 hours, 8 minutes, 41 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹
- Egyptian hieroglyphic
- 𓂍𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓏺
- Greek (Milesian)
- ͵ιηφκαʹ
- Mayan (base 20)
- 𝋢·𝋦·𝋦·𝋡
- Chinese
- 一萬八千五百二十一
- Chinese (financial)
- 壹萬捌仟伍佰貳拾壹
Digit at this position in famous constants
- π — Pi (π)
- Digit 18,521 = 7
- e — Euler's number (e)
- Digit 18,521 = 2
- φ — Golden ratio (φ)
- Digit 18,521 = 5
- √2 — Pythagoras's (√2)
- Digit 18,521 = 8
- ln 2 — Natural log of 2
- Digit 18,521 = 1
- γ — Euler-Mascheroni (γ)
- Digit 18,521 = 7
Also seen as
UTF-8 encoding: E4 A1 99 (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.72.89.
- Address
- 0.0.72.89
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.72.89
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Heard as a frequency, 18,521 Hz is closest to:
- Concert pitch (A4 = 440 Hz): D10 (18794.5 Hz, -25¢)
- Scientific pitch (C4 = 256 Hz): D10 (18390.4 Hz, +12¢)
- Baroque pitch (A4 = 415 Hz): D♯10 (18780.8 Hz, -24¢)
The digit sequence 18521 first appears in π at position 22,932 of the decimal expansion (the 22,932ordinal-suffix:nd 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.
- Mayan numerals — Vigesimal dots-and-bars with a shell zero — one of the earliest true zeros.