Properties of the Number 21862

Twenty-One Thousand Eight Hundred Sixty-Two

Basics

Value: 21861 → 21862 → 21863

Parity: even

Prime: No

Previous Prime: 21859

Next Prime: 21863

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 2 × 17 × 643

Divisors: 1, 2, 17, 34, 643, 1286, 10931, 21862

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010101100110

Octal: 52546

Duodecimal: 1079A

Hexadecimal: 5566

Square: 477947044

Square Root: 147.85804002488334

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 (n+2)X(k+2) 0..2 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 3 or 4. A252075

T(n,k)=Number of (n+1)X(k+1) 0..4 arrays with every 2X2 subblock summing to a prime. A251515

Triangle T(n,k) read by rows; given by [0,1,0,1,0,1,0,1,...] δ [1,1,1,2,1,3,1,4,1,5,1,6,...], where δ is Deléham's operator defined in A084938. A85838

Number of 2's in row n of the Kolakoski fan A143477. A143588

Let c(k) denote the k-th composite number and p(k) the k-th prime number; then a(n) = ∑_{i=n*(n-1)/2+1 .. n*(n+1)/2} c(i) - ∑_i=1..n p(i). A24850

Bond series for first parallel moment of Kagome lattice. A120546

Number of (n+1)X(1+1) 0..4 arrays with every 2X2 subblock summing to a prime. A251508

Number of (n+1)X(3+1) 0..4 arrays with every 2X2 subblock summing to a prime. A251510

Number of (n+2) X (4+2) 0..2 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 3 or 4. A252071

Numbers k such that 445·2^k+1 is prime. A323151