4,021
4,021 is a prime, odd.
4,021 (four thousand twenty-one) is an odd 4-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in binary, 111110110101.
Interestingness
Properties
Primality
4,021 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√4,021 = [63; (2, 2, 3, 8, 6, 4, 1, 1, 6, 1, 9, 1, 2, 2, 1, 9, 1, 6, 1, 1, 4, 6, 8, 3, …)]
Period length 27 — the block in parentheses repeats forever.
Representations
- In words
- four thousand twenty-one
- Ordinal
- 4021st
- Binary
- 111110110101
- Octal
- 7665
- Hexadecimal
- 0xFB5
- Base64
- D7U=
- One's complement
- 61,514 (16-bit)
- Scientific notation
- 4.021 × 10³
- As a duration
- 4,021 s = 1 hour, 7 minutes, 1 second
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹 𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒁹
- Egyptian hieroglyphic
- 𓆼𓆼𓆼𓆼𓎆𓎆𓏺
- Greek (Milesian)
- ͵δκαʹ
- Mayan (base 20)
- 𝋪·𝋡·𝋡
- Chinese
- 四千零二十一
- Chinese (financial)
- 肆仟零貳拾壹
Digit at this position in famous constants
- π — Pi (π)
- Digit 4,021 = 5
- e — Euler's number (e)
- Digit 4,021 = 7
- φ — Golden ratio (φ)
- Digit 4,021 = 5
- √2 — Pythagoras's (√2)
- Digit 4,021 = 7
- ln 2 — Natural log of 2
- Digit 4,021 = 2
- γ — Euler-Mascheroni (γ)
- Digit 4,021 = 0
Also seen as
UTF-8 encoding: E0 BE B5 (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.15.181.
- Address
- 0.0.15.181
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.15.181
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Heard as a frequency, 4,021 Hz is closest to:
- Concert pitch (A4 = 440 Hz): B7 (3951.1 Hz, +30¢)
- Scientific pitch (C4 = 256 Hz): C8 (4096 Hz, -32¢)
- Baroque pitch (A4 = 415 Hz): C8 (3948.2 Hz, +32¢)
The digit sequence 4021 first appears in π at position 9,022 of the decimal expansion (the 9,022ordinal-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.
- Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.