21,990
21,990 is a composite number, even.
Properties
- Parity
- Even
- Digit count
- 5
- Digit sum
- 21
- Digit product
- 0
- Digital root
- 3
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 9,912
- Recamán's sequence
- a(167,783) = 21,990
- Square (n²)
- 483,560,100
- Cube (n³)
- 10,633,486,599,000
- Divisor count
- 16
- σ(n) — sum of divisors
- 52,848
- φ(n) — Euler's totient
- 5,856
- Sum of prime factors
- 743
Primality
Prime factorization: 2 × 3 × 5 × 733
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- twenty-one thousand nine hundred ninety
- Ordinal
- 21990th
- Binary
- 101010111100110
- Octal
- 52746
- Hexadecimal
- 0x55E6
- Base64
- VeY=
- One's complement
- 43,545 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹𒁹 𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋
- Egyptian hieroglyphic
- 𓂍𓂍𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆
- Greek (Milesian)
- ͵καϡϟʹ
- Mayan (base 20)
- 𝋢·𝋮·𝋳·𝋪
- Chinese
- 二萬一千九百九十
- Chinese (financial)
- 貳萬壹仟玖佰玖拾
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,990 = 4
- e — Euler's number (e)
- Digit 21,990 = 8
- φ — Golden ratio (φ)
- Digit 21,990 = 9
- √2 — Pythagoras's (√2)
- Digit 21,990 = 6
- ln 2 — Natural log of 2
- Digit 21,990 = 5
- γ — Euler-Mascheroni (γ)
- Digit 21,990 = 5
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21990, here are decompositions:
- 13 + 21977 = 21990
- 29 + 21961 = 21990
- 47 + 21943 = 21990
- 53 + 21937 = 21990
- 61 + 21929 = 21990
- 79 + 21911 = 21990
- 97 + 21893 = 21990
- 109 + 21881 = 21990
Showing the first eight; more decompositions exist.
UTF-8 encoding: E5 97 A6 (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.85.230.
- Address
- 0.0.85.230
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.85.230
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 21990 first appears in π at position 238,295 of the decimal expansion (the 238,295ordinal-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.