21,388
21,388 is a composite number, even.
Properties
- Parity
- Even
- Digit count
- 5
- Digit sum
- 22
- Digit product
- 384
- Digital root
- 4
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 88,312
- Recamán's sequence
- a(41,063) = 21,388
- Square (n²)
- 457,446,544
- Cube (n³)
- 9,783,866,683,072
- Divisor count
- 6
- σ(n) — sum of divisors
- 37,436
- φ(n) — Euler's totient
- 10,692
- Sum of prime factors
- 5,351
Primality
Prime factorization: 2 2 × 5347
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- twenty-one thousand three hundred eighty-eight
- Ordinal
- 21388th
- Binary
- 101001110001100
- Octal
- 51614
- Hexadecimal
- 0x538C
- Base64
- U4w=
- One's complement
- 44,147 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓂍𓂍𓆼𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ͵κατπηʹ
- Mayan (base 20)
- 𝋢·𝋭·𝋩·𝋨
- Chinese
- 二萬一千三百八十八
- Chinese (financial)
- 貳萬壹仟參佰捌拾捌
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,388 = 6
- e — Euler's number (e)
- Digit 21,388 = 9
- φ — Golden ratio (φ)
- Digit 21,388 = 6
- √2 — Pythagoras's (√2)
- Digit 21,388 = 8
- ln 2 — Natural log of 2
- Digit 21,388 = 4
- γ — Euler-Mascheroni (γ)
- Digit 21,388 = 4
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21388, here are decompositions:
- 5 + 21383 = 21388
- 11 + 21377 = 21388
- 41 + 21347 = 21388
- 47 + 21341 = 21388
- 71 + 21317 = 21388
- 167 + 21221 = 21388
- 197 + 21191 = 21388
- 239 + 21149 = 21388
Showing the first eight; more decompositions exist.
UTF-8 encoding: E5 8E 8C (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.83.140.
- Address
- 0.0.83.140
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.83.140
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 21388 first appears in π at position 469,594 of the decimal expansion (the 469,594ordinal-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.