Properties of the Number -7815

Eight Hundred Fifteen

Basics

Value: -7816 → -7815 → -7814

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 5 × 521

Divisors: 1, 3, 5, 15, 521, 1563, 2605, 7815

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -1111010000111

Octal: -17207

Duodecimal: -4633

Hexadecimal: -1e87

Square: 61074225

Square Root: 88.40248865275231

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 read by rows: T(n, k) = (-1)^{n - k} * binomial(2n + 1, n - k) * L(2k + 1), 0 <= k <= n, where L(k) is the k-th Lucas number (A000032). A326832

Multiples of 15 containing a 15 in their decimal representation. A121035

a(0)=0, a(1)=1, a(2)=2; for n > 2, a(n) = 3·a(n-1) - a(n-2) - 2·a(n-3). A27934

a(n) = floor(n*φ¹³), where φ is the golden ratio, A001622. A4928

Smallest positive number that can be written as sum of distinct Fibonacci numbers in n ways. A13583

T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 1 3 6 or 7. A252321

a(n) = T(n,n-5), array T as in A055807. A55810

Numbers k such that k¹⁸ == 1 (mod 19³). A56089

T(n,k)=Number of nXk zero-sum -2..2 arrays with rows and columns lexicographically nondecreasing. A201496

Smallest k such that k·2*p(n)²-1=q is prime k·2*q²-1=r k·2*r²-1=s, r and s are also prime. A224491