Properties of the Number 15820

Fifteen Thousand Eight Hundred Twenty

Basics

Value: 15819 → 15820 → 15821

Parity: even

Prime: No

Previous Prime: 15817

Next Prime: 15823

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 2 ² × 5 × 7 × 113

Divisors: 1, 2, 4, 5, 7, 10, 14, 20, 28, 35

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2730 Try Today's Challenge

Representations

Binary: 11110111001100

Octal: 36714

Duodecimal: 91A4

Hexadecimal: 3dcc

Square: 250272400

Square Root: 125.777581468241

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

a(n) = ∑_k=1..n lcm(n,k). A51193

The minimal number which has multiplicative persistence 7 in base n. A64871

T(n,k)=Sum of neighbor maps: number of nXk binary arrays indicating the locations of corresponding elements equal to the sum mod 4 of their horizontal and antidiagonal neighbors in a random 0..3 nXk array. A222935

T(n,k)=Sum of neighbor maps: number of nXk binary arrays indicating the locations of corresponding elements equal to the sum mod 4 of their horizontal and vertical neighbors in a random 0..3 nXk array. A220805

Number of lines through exactly 5 points of an n X n grid of points. A18812

Positions of powers of 2 in A064413. A64954

G.f. satisfies: 24·A(x) = 23 + 64·x + A(x)⁸, starting with [1,4,28]. A120604

a(n) = floor(((1+sqrt(3))/2)ⁿ). A125895

Triangular array read by rows. T(n,k) is the number of 2-colored labeled graphs on n nodes with exactly k edges; n >= 0, 0 <= k <= A002620(n). A228890

Irregular triangle read by rows: T(n,k) = number of size k subsets of S_n that remain unchanged under the operation of replacing a permutation with its inverse. A277081