21,000
21,000 is a composite number, even.
Properties
Primality
Prime factorization: 2 3 × 3 × 5 3 × 7
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- twenty-one thousand
- Ordinal
- 21000th
- Binary
- 101001000001000
- Octal
- 51010
- Hexadecimal
- 0x5208
- Base64
- Ugg=
- One's complement
- 44,535 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋 ·
- Egyptian hieroglyphic
- 𓂍𓂍𓆼
- Greek (Milesian)
- ͵κα
- Mayan (base 20)
- 𝋢·𝋬·𝋪·𝋠
- Chinese
- 二萬一千
- Chinese (financial)
- 貳萬壹仟
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,000 = 1
- e — Euler's number (e)
- Digit 21,000 = 0
- φ — Golden ratio (φ)
- Digit 21,000 = 6
- √2 — Pythagoras's (√2)
- Digit 21,000 = 4
- ln 2 — Natural log of 2
- Digit 21,000 = 0
- γ — Euler-Mascheroni (γ)
- Digit 21,000 = 0
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21000, here are decompositions:
- 17 + 20983 = 21000
- 19 + 20981 = 21000
- 37 + 20963 = 21000
- 41 + 20959 = 21000
- 53 + 20947 = 21000
- 61 + 20939 = 21000
- 71 + 20929 = 21000
- 79 + 20921 = 21000
Showing the first eight; more decompositions exist.
UTF-8 encoding: E5 88 88 (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.8.
- Address
- 0.0.82.8
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.82.8
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 21000 first appears in π at position 158,074 of the decimal expansion (the 158,074ordinal-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.