21,390
21,390 is a composite number, even.
Properties
- Parity
- Even
- Digit count
- 5
- Digit sum
- 15
- Digit product
- 0
- Digital root
- 6
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 9,312
- Recamán's sequence
- a(41,059) = 21,390
- Square (n²)
- 457,532,100
- Cube (n³)
- 9,786,611,619,000
- Divisor count
- 32
- σ(n) — sum of divisors
- 55,296
- φ(n) — Euler's totient
- 5,280
- Sum of prime factors
- 64
Primality
Prime factorization: 2 × 3 × 5 × 23 × 31
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- twenty-one thousand three hundred ninety
- Ordinal
- 21390th
- Binary
- 101001110001110
- Octal
- 51616
- Hexadecimal
- 0x538E
- Base64
- U44=
- One's complement
- 44,145 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋
- Egyptian hieroglyphic
- 𓂍𓂍𓆼𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆
- Greek (Milesian)
- ͵κατϟʹ
- Mayan (base 20)
- 𝋢·𝋭·𝋩·𝋪
- Chinese
- 二萬一千三百九十
- Chinese (financial)
- 貳萬壹仟參佰玖拾
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,390 = 9
- e — Euler's number (e)
- Digit 21,390 = 0
- φ — Golden ratio (φ)
- Digit 21,390 = 1
- √2 — Pythagoras's (√2)
- Digit 21,390 = 1
- ln 2 — Natural log of 2
- Digit 21,390 = 1
- γ — Euler-Mascheroni (γ)
- Digit 21,390 = 9
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21390, here are decompositions:
- 7 + 21383 = 21390
- 11 + 21379 = 21390
- 13 + 21377 = 21390
- 43 + 21347 = 21390
- 67 + 21323 = 21390
- 71 + 21319 = 21390
- 73 + 21317 = 21390
- 107 + 21283 = 21390
Showing the first eight; more decompositions exist.
UTF-8 encoding: E5 8E 8E (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.83.142.
- Address
- 0.0.83.142
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.83.142
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 21390 first appears in π at position 172,429 of the decimal expansion (the 172,429ordinal-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.