21,008
21,008 is a composite number, even.
Properties
- Parity
- Even
- Digit count
- 5
- Digit sum
- 11
- Digit product
- 0
- Digital root
- 2
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 80,012
- Recamán's sequence
- a(41,823) = 21,008
- Square (n²)
- 441,336,064
- Cube (n³)
- 9,271,588,032,512
- Divisor count
- 20
- σ(n) — sum of divisors
- 44,268
- φ(n) — Euler's totient
- 9,600
- Sum of prime factors
- 122
Primality
Prime factorization: 2 4 × 13 × 101
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- twenty-one thousand eight
- Ordinal
- 21008th
- Binary
- 101001000010000
- Octal
- 51020
- Hexadecimal
- 0x5210
- Base64
- UhA=
- One's complement
- 44,527 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋 𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓂍𓂍𓆼𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ͵καηʹ
- Mayan (base 20)
- 𝋢·𝋬·𝋪·𝋨
- Chinese
- 二萬一千零八
- Chinese (financial)
- 貳萬壹仟零捌
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,008 = 5
- e — Euler's number (e)
- Digit 21,008 = 1
- φ — Golden ratio (φ)
- Digit 21,008 = 5
- √2 — Pythagoras's (√2)
- Digit 21,008 = 1
- ln 2 — Natural log of 2
- Digit 21,008 = 9
- γ — Euler-Mascheroni (γ)
- Digit 21,008 = 8
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21008, here are decompositions:
- 7 + 21001 = 21008
- 61 + 20947 = 21008
- 79 + 20929 = 21008
- 109 + 20899 = 21008
- 151 + 20857 = 21008
- 199 + 20809 = 21008
- 277 + 20731 = 21008
- 367 + 20641 = 21008
Showing the first eight; more decompositions exist.
UTF-8 encoding: E5 88 90 (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.16.
- Address
- 0.0.82.16
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.82.16
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 21008 first appears in π at position 8,279 of the decimal expansion (the 8,279ordinal-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.