Properties of the Number -21987

Twenty-One Thousand Nine Hundred Eighty-Seven

Basics

Value: -21988 → -21987 → -21986

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 7 × 349

Divisors: 1, 3, 7, 9, 21, 63, 349, 1047, 2443, 3141

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -101010111100011

Octal: -52743

Duodecimal: -10883

Hexadecimal: -55e3

Square: 483428169

Square Root: 148.28014027508877

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

Consider the base-8 Kaprekar map n->K(n) defined in A165090. Sequence gives numbers belonging to cycles, including fixed points. A165095

Consider the base-8 Kaprekar map n->K(n) defined in A165090. Sequence gives numbers belonging to cycles of length greater than 1. A165097

Number of partitions p of n such that mean(p) < multiplicity(min(p)). A240203

Number of partitions p of n such that mean(p) <= multiplicity(min(p)). A240204

Place a point on the integer coordinates, up to |n|, along all four axial directions on a Cartesian plane, and then join a circle through every unordered triple of non-collinear points: a(n) is the number of distinct circles created. A385159

Complement of A269020: numbers not of the form ceiling(n^1+1/n). A269023

Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 17 ones. A31785

L-th order palindromes with L > 2. A89381

Number of (5+2) X (n+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 0 3 5 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 0 3 5 6 or 7. A252389