Properties of the Number 15640

Fifteen Thousand Six Hundred Forty

Basics

Value: 15639 → 15640 → 15641

Parity: even

Prime: No

Previous Prime: 15629

Next Prime: 15641

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 2 ³ × 5 × 17 × 23

Divisors: 1, 2, 4, 5, 8, 10, 17, 20, 23, 34

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11110100011000

Octal: 36430

Duodecimal: 9074

Hexadecimal: 3d18

Square: 244609600

Square Root: 125.05998560690786

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

Triangle T, read by rows, equal to the matrix square of A118032 and also equal to a diagonal bisection of A118032; i.e., diagonal n of T equals diagonal 2n of A118032: T(n,k) = A118032(2n-k,k) for n>=k>=0. A118040

T(n,k)=Number of length n+5 0..k arrays with no disjoint triples in any consecutive six terms having the same sum. A247995

T(n,k)=Number of (n+3)X(k+3) 0..1 arrays with each row divisible by 15 and column not divisible by 15, read as a binary number with top and left being the most significant bits. A263124

Column 1 of triangle A118032, where column 1 of the matrix square of A118032 forms a bisection of this sequence. A118034

G.f. A(x) satisfies: R(x²*A(x)) = x³ - x⁴, where R(A(x)) = x. A350433

Numbers k such that k+1, k+3, k+7 and k+9 are all primes. A125855

Starts of runs of 5 consecutive even numbers that are all totient numbers (A002202). A333022

a(n) = n*(n-1)*(n+1)*(3·n-2)/12. A153978

a(n) = ∑_{k=0..floor(n/3)} binomial(4·n-3·k,n-3·k). A387990

Column 1 of triangle A118040, which is the matrix square of triangle A118032; also equals a bisection of A118034, which is column 1 of A118032. A118042