Properties of the Number 20843

Twenty Thousand Eight Hundred Forty-Three

Basics

Value: 20842 → 20843 → 20844

Parity: odd

Prime: No

Previous Prime: 20809

Next Prime: 20849

Digit Sum: 17

Digital Root: 8

Palindrome: No

Factorization: 19 × 1097

Divisors: 1, 19, 1097, 20843

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000101101011

Octal: 50553

Duodecimal: 1008B

Hexadecimal: 516b

Square: 434430649

Square Root: 144.37104972950775

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

Expansion of 1/(1 - x*∏_k>=1 1/(1 - x^k)^k). A299166

Relative of Hofstadter Q-sequence: a(n) = max(0, n+20830) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 0. A283887

a(n+1) = 2a(n)-a([n/2]) starting with a(0)=0 and a(1)=1. A62178

Floor(r·a(n-1)) + floor(r·a(n-2)), where r = 5/3, a(0) = 1, a(1) = 1. A275864

Unicode codes for the Han digits. A61745

Number of partitions of n with difference -7 between the number of odd parts and the number of even parts, both counted without multiplicity. A242685

Primes p such that (2^p - 2^(p+1/2) + 1)/5 is prime. A125742

Decimal expansion of 1/sqrt(86). A20843

Number of 7Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 1 0 vertically. A207116