Properties of the Number 21689

Twenty-One Thousand Six Hundred Eighty-Nine

Basics

Value: 21688 → 21689 → 21690

Parity: odd

Prime: No

Previous Prime: 21683

Next Prime: 21701

Digit Sum: 26

Digital Root: 8

Palindrome: No

Factorization: 23 ² × 41

Divisors: 1, 23, 41, 529, 943, 21689

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010010111001

Octal: 52271

Duodecimal: 10675

Hexadecimal: 54b9

Square: 470412721

Square Root: 147.27185746095552

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

Numbers k such that the fractional part of (1024/1000)^k is greater than 1-(1/k). A153680

Composites whose prime factorization in base 8 is an anagram of the number in base 8. A260052

Number of integer partitions of n with reverse-alternating product > 1. A347449

Number of vertices formed in a square by straight line segments when connecting the n+1 points along each edge that divide it into n equal parts to the n+1 points on the edge on the opposite side of the square. A355839

Numerators of row 4 of table described in A051714/A051715. A51722

a(n) = greatest k such that A155043(k+A262509(n)) < A155043(A262509(n)). A262909

a(n) = (2·n - 5)n². A15240

Number of positive terms in row n of A082268. A82269

Numbers k such that 17^k - 16 is prime. A34922

Number of nX2 0..3 arrays with values 0..3 introduced in row major order, the number of instances of each value within one of each other, and every element equal to one or two horizontal or vertical neighbors. A199359