Properties of the Number 27981

Twenty-Seven Thousand Nine Hundred Eighty-One

Basics

Value: 27980 → 27981 → 27982

Parity: odd

Prime: No

Previous Prime: 27967

Next Prime: 27983

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 3109

Divisors: 1, 3, 9, 3109, 9327, 27981

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 110110101001101

Octal: 66515

Duodecimal: 14239

Hexadecimal: 6d4d

Square: 782936361

Square Root: 167.2752223134078

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

Triangle T(n, k, m) = (m*(n-k) + 1)*T(n-1, k-1, m) + (m·k + 1)*T(n-1, k, m) + m·k*(n-k)*T(n-2, k-1, m) with T(n, 0, m) = T(n, n, m) = 1 and m = 5, read by rows. A157151

a(n) = ∑_i=0..n digsum(i)³, where digsum(i) = A007953(i). A231688

Sieve performed by successive iterations of steps where step m is: keep m terms, remove the next 3 and repeat; as m = 1,2,3,.. the remaining terms form this sequence. A112561

Number of integer partitions of n with frequency depth round(sqrt(n)). A325271

Number of integer partitions of n with frequency depth floor(sqrt(n)). A325252

a(n) is the end square spiral number for a knight starting on square n moving on a board with squares numbered with the square of their distance from the 0-square origin and where the knight moves to the smallest numbered unvisited square; the smallest spiral number ordering is used if the distances are equal. A326931

a(n) = greatest number in row n of the array in A225485. A364810

a(n) = ∑_k=0..2·n (k+1)*T(n,k), T given by A027960. A27981

Number of nX4 0..1 arrays with each 1 adjacent to 3 or 5 king-move neighboring 1s. A296153