21,221
21,221 is a prime, odd.
21,221 (twenty-one thousand two hundred twenty-one) is an odd 5-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in hexadecimal, 0x52E5.
Interestingness
Properties
- Parity
- Odd
- Digit count
- 5
- Digit sum
- 8
- Digit product
- 8
- Digital root
- 8
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 12,212
- Recamán's sequence
- a(41,397) = 21,221
- Square (n²)
- 450,330,841
- Cube (n³)
- 9,556,470,776,861
- Divisor count
- 2
- σ(n) — sum of divisors
- 21,222
- φ(n) — Euler's totient
- 21,220
Primality
21,221 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√21,221 = [145; (1, 2, 14, 4, 3, 1, 1, 2, 2, 1, 7, 1, 1, 1, 1, 1, 2, 10, 41, 1, 1, 9, 1, 1, …)]
Representations
- In words
- twenty-one thousand two hundred twenty-one
- Ordinal
- 21221st
- Binary
- 101001011100101
- Octal
- 51345
- Hexadecimal
- 0x52E5
- Base64
- UuU=
- One's complement
- 44,314 (16-bit)
- Scientific notation
- 2.1221 × 10⁴
- As a duration
- 21,221 s = 5 hours, 53 minutes, 41 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹
- Egyptian hieroglyphic
- 𓂍𓂍𓆼𓍢𓍢𓎆𓎆𓏺
- Greek (Milesian)
- ͵κασκαʹ
- Mayan (base 20)
- 𝋢·𝋭·𝋡·𝋡
- Chinese
- 二萬一千二百二十一
- Chinese (financial)
- 貳萬壹仟貳佰貳拾壹
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,221 = 5
- e — Euler's number (e)
- Digit 21,221 = 3
- φ — Golden ratio (φ)
- Digit 21,221 = 5
- √2 — Pythagoras's (√2)
- Digit 21,221 = 5
- ln 2 — Natural log of 2
- Digit 21,221 = 1
- γ — Euler-Mascheroni (γ)
- Digit 21,221 = 1
Also seen as
UTF-8 encoding: E5 8B A5 (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.229.
- Address
- 0.0.82.229
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.82.229
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 21221 first appears in π at position 8,730 of the decimal expansion (the 8,730ordinal-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
- Prime numbers — The building blocks of arithmetic: what primes are, why they matter, and how we find them.
- Mayan numerals — Vigesimal dots-and-bars with a shell zero — one of the earliest true zeros.