Properties of the Number 19815

Nineteen Thousand Eight Hundred Fifteen

Basics

Value: 19814 → 19815 → 19816

Parity: odd

Prime: No

Previous Prime: 19813

Next Prime: 19819

Digit Sum: 24

Digital Root: 6

Palindrome: No

Factorization: 3 × 5 × 1321

Divisors: 1, 3, 5, 15, 1321, 3963, 6605, 19815

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 100110101100111

Octal: 46547

Duodecimal: B573

Hexadecimal: 4d67

Square: 392634225

Square Root: 140.76576288288285

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

Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of B(x)^k, where B(x) is the g.f. of A381574. A381573

a(n) is the index of A384793(n) in A038618. A384794

Half the number of length n integer sequences with sum zero and sum of squares 242. A157543

Transform of A056594 by the T_1,1 transformation (see link). A159334

Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 217", based on the 5-celled von Neumann neighborhood. A270911

a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = A001950 (upper Wythoff sequence). A24689

s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = [ n/2 ], s = A001950 (upper Wythoff sequence). A25122

a(n) = 2ⁿ + binomial(n, floor(n/2)) - 1. A261681

Decimal expansion of sine of 6 degrees. A19815

O.g.f. A(x) satisfies: [xⁿ] exp( x·A(x) ) * (n² + 1 - A(x)) = 0 for n >= 0. A305114