Properties of the Number 21375

Twenty-One Thousand Three Hundred Seventy-Five

Basics

Value: 21374 → 21375 → 21376

Parity: odd

Prime: No

Previous Prime: 21347

Next Prime: 21377

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 5 ³ × 19

Divisors: 1, 3, 5, 9, 15, 19, 25, 45, 57, 75

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101001101111111

Octal: 51577

Duodecimal: 10453

Hexadecimal: 537f

Square: 456890625

Square Root: 146.20191517213445

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..3 arrays with every 3X3 subblock row and column sum equal to 0 3 5 6 or 7 and every 3X3 diagonal and antidiagonal sum not equal to 0 3 5 6 or 7. A252148

Number of ways to place 2 points on a triangular grid of side n so that they are not adjacent. A239568

Related to label-increasing forests with branching bounded by 3. A297198

T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 3, 4 or 6 king-move adjacent elements, with upper left element zero. A298337

T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 3, 4, 6 or 8 king-move adjacent elements, with upper left element zero. A299398

a(n) = ∑_k=1..n binomial(n*(m+1)-m·k-1, n-k)*k/(n·m-(m-1)*k), for m=7. A376447

Decimal representation of the diagonal from the origin to the corner of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 777", based on the 5-celled von Neumann neighborhood. A290293

Number of compositions of n such that the smallest part has multiplicity four. A241864

Number of nX3 0..1 arrays with every element equal to 1, 2, 3, 4 or 6 king-move adjacent elements, with upper left element zero. A298332

The Wiener index of the Kneser graph K(n,2) (n>=5). A228306