21,020
21,020 is a composite number, even.
Properties
- Parity
- Even
- Digit count
- 5
- Digit sum
- 5
- Digit product
- 0
- Digital root
- 5
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 2,012
- Recamán's sequence
- a(41,799) = 21,020
- Square (n²)
- 441,840,400
- Cube (n³)
- 9,287,485,208,000
- Divisor count
- 12
- σ(n) — sum of divisors
- 44,184
- φ(n) — Euler's totient
- 8,400
- Sum of prime factors
- 1,060
Primality
Prime factorization: 2 2 × 5 × 1051
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- twenty-one thousand twenty
- Ordinal
- 21020th
- Binary
- 101001000011100
- Octal
- 51034
- Hexadecimal
- 0x521C
- Base64
- Uhw=
- One's complement
- 44,515 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋 𒌋𒌋
- Egyptian hieroglyphic
- 𓂍𓂍𓆼𓎆𓎆
- Greek (Milesian)
- ͵κακʹ
- Mayan (base 20)
- 𝋢·𝋬·𝋫·𝋠
- Chinese
- 二萬一千零二十
- Chinese (financial)
- 貳萬壹仟零貳拾
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,020 = 9
- e — Euler's number (e)
- Digit 21,020 = 5
- φ — Golden ratio (φ)
- Digit 21,020 = 9
- √2 — Pythagoras's (√2)
- Digit 21,020 = 0
- ln 2 — Natural log of 2
- Digit 21,020 = 9
- γ — Euler-Mascheroni (γ)
- Digit 21,020 = 2
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21020, here are decompositions:
- 3 + 21017 = 21020
- 7 + 21013 = 21020
- 19 + 21001 = 21020
- 37 + 20983 = 21020
- 61 + 20959 = 21020
- 73 + 20947 = 21020
- 163 + 20857 = 21020
- 211 + 20809 = 21020
Showing the first eight; more decompositions exist.
UTF-8 encoding: E5 88 9C (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.28.
- Address
- 0.0.82.28
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.82.28
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 21020 first appears in π at position 139,656 of the decimal expansion (the 139,656ordinal-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.