Properties of the Number 20946

Twenty Thousand Nine Hundred Forty-Six

Basics

Value: 20945 → 20946 → 20947

Parity: even

Prime: No

Previous Prime: 20939

Next Prime: 20947

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 2 × 3 × 3491

Divisors: 1, 2, 3, 6, 3491, 6982, 10473, 20946

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000111010010

Octal: 50722

Duodecimal: 10156

Hexadecimal: 51d2

Square: 438734916

Square Root: 144.7273298309618

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

Number of inequivalent ways (mod D₄) a pair of checkers can be placed on an n X n board. A14409

T(n,k)=Number of length (n+k)X1 arrays of occupancy after each element moves up to +-k places but not 0 and without 2-loops. A222165

Let p = n-th irregular prime, A000928(n). Then a(n) = smallest value of m such that numerator(Bernoulli(2·m)/(2·m)) / numerator(Bernoulli(2·m)/(2·m*(2·m-1))) equals p. A92291

Irregular triangle read by rows: T(n,k) is the number of free polyominoes with n cells having k regions between the polyominoes and their bounding boxes, n >= 1, k >= 0. A380282

a(n) = 121·n² - 204·n + 86. A157440

Number T(m,n) of series-reduced free trees with n nodes of which exactly m >= 3 are leaves, m+1 <= n <= 2m-2. A271205

Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,21. A64247

Values of n such that N=(an+1)(bn+1)(cn+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,35. A64254

a(n) = number of ways to dispose two pawns on a chessboard of size n X n (two dispositions are equivalent if one can be rotated or reflected to give the other one). A141582

Number of partitions satisfying cn(0,5) <= cn(1,5) + cn(4,5) + cn(2,5) and cn(0,5) <= cn(1,5) + cn(4,5) + cn(3,5). A39844