21,090
21,090 is a composite number, even.
21,090 (twenty-one thousand ninety) is an even 5-digit number. It is a composite number with 32 divisors, and factors as 2 × 3 × 5 × 19 × 37. Its proper divisors sum to 33,630, more than the number itself, making it an abundant number. Written other ways, in hexadecimal, 0x5262.
Interestingness
Properties
- Parity
- Even
- Digit count
- 5
- Digit sum
- 12
- Digit product
- 0
- Digital root
- 3
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 9,012
- Recamán's sequence
- a(41,659) = 21,090
- Square (n²)
- 444,788,100
- Cube (n³)
- 9,380,581,029,000
- Divisor count
- 32
- σ(n) — sum of divisors
- 54,720
- φ(n) — Euler's totient
- 5,184
- Sum of prime factors
- 66
Primality
Prime factorization: 2 × 3 × 5 × 19 × 37
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√21,090 = [145; (4, 2, 6, 1, 1, 1, 3, 2, 3, 1, 1, 1, 6, 2, 4, 290)]
Period length 16 — the block in parentheses repeats forever.
Representations
- In words
- twenty-one thousand ninety
- Ordinal
- 21090th
- Binary
- 101001001100010
- Octal
- 51142
- Hexadecimal
- 0x5262
- Base64
- UmI=
- One's complement
- 44,445 (16-bit)
- Scientific notation
- 2.109 × 10⁴
- As a duration
- 21,090 s = 5 hours, 51 minutes, 30 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹 𒌋𒌋𒌋
- Egyptian hieroglyphic
- 𓂍𓂍𓆼𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆
- Greek (Milesian)
- ͵καϟʹ
- Mayan (base 20)
- 𝋢·𝋬·𝋮·𝋪
- Chinese
- 二萬一千零九十
- Chinese (financial)
- 貳萬壹仟零玖拾
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,090 = 9
- e — Euler's number (e)
- Digit 21,090 = 0
- φ — Golden ratio (φ)
- Digit 21,090 = 0
- √2 — Pythagoras's (√2)
- Digit 21,090 = 9
- ln 2 — Natural log of 2
- Digit 21,090 = 6
- γ — Euler-Mascheroni (γ)
- Digit 21,090 = 9
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21090, here are decompositions:
- 23 + 21067 = 21090
- 29 + 21061 = 21090
- 31 + 21059 = 21090
- 59 + 21031 = 21090
- 67 + 21023 = 21090
- 71 + 21019 = 21090
- 73 + 21017 = 21090
- 79 + 21011 = 21090
Showing the first eight; more decompositions exist.
UTF-8 encoding: E5 89 A2 (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.98.
- Address
- 0.0.82.98
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.82.98
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 21090 first appears in π at position 35,326 of the decimal expansion (the 35,326ordinal-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.
Related reading
- Babylonian numerals — The base-60 cuneiform system that gave us 60 minutes, 60 seconds, and 360°.