Properties of the Number 20812

Twenty Thousand Eight Hundred Twelve

Basics

Value: 20811 → 20812 → 20813

Parity: even

Prime: No

Previous Prime: 20809

Next Prime: 20849

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 2 ² × 11 ² × 43

Divisors: 1, 2, 4, 11, 22, 43, 44, 86, 121, 172

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101000101001100

Octal: 50514

Duodecimal: 10064

Hexadecimal: 514c

Square: 433139344

Square Root: 144.263647534644

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

a(n) = (2·n - 1)*n². A15237

25-gonal numbers: a(n) = n*(23·n-21)/2. A255184

Numbers k such that 6·10^k+1 is prime. A56805

Row sums of the triangle in A199332. A199771

T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with the maximum plus the upper median plus the lower median plus the minimum of every 2X2 subblock differing from its horizontal and vertical neighbors by exactly one. A237375

a(n) = number of steps to reach 0 when starting from k = n³ and repeatedly applying the map that replaces k with k - A055401(k), where A055401(k) = the number of positive cubes needed to sum to k using the greedy algorithm. A261227

Row sums of A128623. A128624

Number of 0..n arrays x(0..2) of 3 elements with each no smaller than the sum of its previous elements modulo (n+1). A200252

Number of (w,x,y,z) with all terms in {0,...,n}, w even, and x = y + z. A212760

a(n) = floor(average of first n cubes). A78618