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Properties of the Number -7821

Eight Hundred Twenty-One

Basics

Value: -7822 → -7821 → -7820

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 2 × 11 × 79

Divisors: 1, 3, 9, 11, 33, 79, 99, 237, 711, 869

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -1111010001101

Octal: -17215

Duodecimal: -4639

Hexadecimal: -1e8d

Square: 61168041

Square Root: 88.43641783790206

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+1)X(k+1) arrays of permutations of 0..(n+1)*(k+1)-1 with each element having directed index change 0,0 0,1 1,0 -1,-2 or 0,2. A264313
T(n,k)=Number of nondecreasing -k..k vectors of length n whose dot product with some nondecreasing -k..k vector equals n. A226410
Natural numbers n that have the property that starting from k = n, the fixed point of the map k -> floor(tan(k)) is strictly positive, while the smallest number encountered during the iteration is strictly negative. A258202
Square array A(n,k), n >= 0, k >= 1, read by antidiagonals, where column k is the expansion of e.g.f. exp(∑j=1..k j2*xj). A293724
Numbers that have exactly 5 representations as a k-gonal number, P(n,k) = n*((k-2)*n - (k-4))/2, k and n >= 3. A321156
a(n) is nonsquarefree and is sum of first k nonsquarefrees for some k. A13935
In the binary race of π, where the race leader changes. A278920
Numbers which are the product of two S-primes (A057948) in exactly two ways. A343827
a(n) = ∑k=1..n nfloor(n/k - 1). A345030
Square array T(n,k), n >= 1, k >= 0, read by antidiagonals downwards, where T(n,k) = ∑j=1..n kfloor(n/j - 1). A345032