Properties of the Number 21969

Twenty-One Thousand Nine Hundred Sixty-Nine

Basics

Value: 21968 → 21969 → 21970

Parity: odd

Prime: No

Previous Prime: 21961

Next Prime: 21977

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 2441

Divisors: 1, 3, 9, 2441, 7323, 21969

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010111010001

Octal: 52721

Duodecimal: 10869

Hexadecimal: 55d1

Square: 482636961

Square Root: 148.2194319244275

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

T(n,k)=Number of nXk 0..4 arrays with each element·equal to the number of its horizontal and vertical neighbors equal to 3,0,1,2,4 for x=0,1,2,3,4. A196218

Row 5 of A277710: Positions of 5's in A264977; positions of 10's in A277330. A277715

Expansion of (1-x)/(1-x+x²+2·x³). A78017

a(n) = n³ + 17. A84379

Row sums of triangle A171840. A171841

Number of (w,x,y,z) with all terms in {1,...,n} and w <= (geometric mean of x,y,z). A212143

Numbers k for which 5·k-4, 5·k-2, 5·k+2, and 5·k+4 are primes. A178082

Number of nX3 0..4 arrays with each element·equal to the number its horizontal and vertical neighbors equal to 3,0,1,2,4 for x=0,1,2,3,4. A196213

Number of nX7 0..4 arrays with each element·equal to the number its horizontal and vertical neighbors equal to 3,0,1,2,4 for x=0,1,2,3,4. A196217

Number of graphs on n labeled nodes with degree at most 3. A136282