18,121
18,121 is a prime, odd.
18,121 (eighteen 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, 0x46C9.
Interestingness
Properties
- Parity
- Odd
- Digit count
- 5
- Digit sum
- 13
- Digit product
- 16
- Digital root
- 4
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 12,181
- Recamán's sequence
- a(15,602) = 18,121
- Square (n²)
- 328,370,641
- Cube (n³)
- 5,950,404,385,561
- Divisor count
- 2
- σ(n) — sum of divisors
- 18,122
- φ(n) — Euler's totient
- 18,120
Primality
18,121 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√18,121 = [134; (1, 1, 1, 1, 2, 4, 1, 8, 2, 7, 1, 2, 5, 1, 1, 1, 2, 1, 16, 9, 1, 10, 3, 6, …)]
Representations
- In words
- eighteen thousand one hundred twenty-one
- Ordinal
- 18121st
- Binary
- 100011011001001
- Octal
- 43311
- Hexadecimal
- 0x46C9
- Base64
- Rsk=
- One's complement
- 47,414 (16-bit)
- Scientific notation
- 1.8121 × 10⁴
- As a duration
- 18,121 s = 5 hours, 2 minutes, 1 second
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒁹𒁹 𒁹
- Egyptian hieroglyphic
- 𓂍𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓍢𓎆𓎆𓏺
- Greek (Milesian)
- ͵ιηρκαʹ
- Mayan (base 20)
- 𝋢·𝋥·𝋦·𝋡
- Chinese
- 一萬八千一百二十一
- Chinese (financial)
- 壹萬捌仟壹佰貳拾壹
Digit at this position in famous constants
- π — Pi (π)
- Digit 18,121 = 3
- e — Euler's number (e)
- Digit 18,121 = 7
- φ — Golden ratio (φ)
- Digit 18,121 = 2
- √2 — Pythagoras's (√2)
- Digit 18,121 = 5
- ln 2 — Natural log of 2
- Digit 18,121 = 5
- γ — Euler-Mascheroni (γ)
- Digit 18,121 = 9
Also seen as
UTF-8 encoding: E4 9B 89 (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.70.201.
- Address
- 0.0.70.201
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.70.201
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Heard as a frequency, 18,121 Hz is closest to:
- Concert pitch (A4 = 440 Hz): C♯10 (17739.7 Hz, +37¢)
- Scientific pitch (C4 = 256 Hz): D10 (18390.4 Hz, -26¢)
- Baroque pitch (A4 = 415 Hz): D10 (17726.7 Hz, +38¢)
The digit sequence 18121 first appears in π at position 297,024 of the decimal expansion (the 297,024ordinal-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.