21,440
21,440 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
- 4,412
- Recamán's sequence
- a(40,959) = 21,440
- Square (n²)
- 459,673,600
- Cube (n³)
- 9,855,401,984,000
- Divisor count
- 28
- σ(n) — sum of divisors
- 51,816
- φ(n) — Euler's totient
- 8,448
- Sum of prime factors
- 84
Primality
Prime factorization: 2 6 × 5 × 67
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- twenty-one thousand four hundred forty
- Ordinal
- 21440th
- Binary
- 101001111000000
- Octal
- 51700
- Hexadecimal
- 0x53C0
- Base64
- U8A=
- One's complement
- 44,095 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋
- Egyptian hieroglyphic
- 𓂍𓂍𓆼𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆
- Greek (Milesian)
- ͵καυμʹ
- Mayan (base 20)
- 𝋢·𝋭·𝋬·𝋠
- Chinese
- 二萬一千四百四十
- Chinese (financial)
- 貳萬壹仟肆佰肆拾
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,440 = 1
- e — Euler's number (e)
- Digit 21,440 = 9
- φ — Golden ratio (φ)
- Digit 21,440 = 3
- √2 — Pythagoras's (√2)
- Digit 21,440 = 4
- ln 2 — Natural log of 2
- Digit 21,440 = 9
- γ — Euler-Mascheroni (γ)
- Digit 21,440 = 8
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21440, here are decompositions:
- 7 + 21433 = 21440
- 43 + 21397 = 21440
- 61 + 21379 = 21440
- 127 + 21313 = 21440
- 157 + 21283 = 21440
- 163 + 21277 = 21440
- 193 + 21247 = 21440
- 229 + 21211 = 21440
Showing the first eight; more decompositions exist.
UTF-8 encoding: E5 8F 80 (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.83.192.
- Address
- 0.0.83.192
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.83.192
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 21440 first appears in π at position 160,512 of the decimal expansion (the 160,512ordinal-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.