21,542
21,542 is a composite number, even.
Properties
- Parity
- Even
- Digit count
- 5
- Digit sum
- 14
- Digit product
- 80
- Digital root
- 5
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 24,512
- Recamán's sequence
- a(40,755) = 21,542
- Square (n²)
- 464,057,764
- Cube (n³)
- 9,996,732,352,088
- Divisor count
- 4
- σ(n) — sum of divisors
- 32,316
- φ(n) — Euler's totient
- 10,770
- Sum of prime factors
- 10,773
Primality
Prime factorization: 2 × 10771
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- twenty-one thousand five hundred forty-two
- Ordinal
- 21542nd
- Binary
- 101010000100110
- Octal
- 52046
- Hexadecimal
- 0x5426
- Base64
- VCY=
- One's complement
- 43,993 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒁹𒁹
- Egyptian hieroglyphic
- 𓂍𓂍𓆼𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓏺𓏺
- Greek (Milesian)
- ͵καφμβʹ
- Mayan (base 20)
- 𝋢·𝋭·𝋱·𝋢
- Chinese
- 二萬一千五百四十二
- Chinese (financial)
- 貳萬壹仟伍佰肆拾貳
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,542 = 7
- e — Euler's number (e)
- Digit 21,542 = 9
- φ — Golden ratio (φ)
- Digit 21,542 = 8
- √2 — Pythagoras's (√2)
- Digit 21,542 = 4
- ln 2 — Natural log of 2
- Digit 21,542 = 8
- γ — Euler-Mascheroni (γ)
- Digit 21,542 = 8
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21542, here are decompositions:
- 13 + 21529 = 21542
- 19 + 21523 = 21542
- 43 + 21499 = 21542
- 61 + 21481 = 21542
- 109 + 21433 = 21542
- 151 + 21391 = 21542
- 163 + 21379 = 21542
- 223 + 21319 = 21542
Showing the first eight; more decompositions exist.
UTF-8 encoding: E5 90 A6 (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.84.38.
- Address
- 0.0.84.38
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.84.38
Unspecified address (0.0.0.0/8) — "this network" placeholder.
This passes the ABA routing number checksum and matches the Federal Reserve numbering scheme.
Banks operate many routing numbers per state and division; an unmatched checksum-valid number can still be a real RTN at a smaller institution.
The digit sequence 21542 first appears in π at position 46,321 of the decimal expansion (the 46,321ordinal-suffix:st 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.