Properties of the Number -30721

Thirty Thousand Seven Hundred Twenty-One

Basics

Value: -30722 → -30721 → -30720

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 31 × 991

Divisors: 1, 31, 991, 30721

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -111100000000001

Octal: -74001

Duodecimal: -15941

Hexadecimal: -7801

Square: 943779841

Square Root: 175.2740711000917

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

Diagonal in array of n-gonal numbers A081422. A81437

a(n) = 15·2ⁿ⁺¹ + 1. A195744

a(n) = a(n-1) + a(m) for n >= 4, where m = 2·n - 2 - 2^p+1 and p is the unique integer such that 2^p < n - 1 <= 2^p+1, starting with a(1) = a(2) = 1 and a(3) = 3. A50035

T(n,k)=Number of n X k 0..1 arrays with each 1 adjacent to 0 or 3 king-move neighboring 1s. A295918

Number of singular 2 X 2 matrices over Z(n) (i.e., with determinant = 0). A20478

a(n) = 30·n² + 1. A158558

E.g.f. satisfies: A'(x) = A(x)⁶ / A(-x) with A(0) = 1. A235370

Number of pairs with two different elements which can be obtained by selecting unique elements from two sets with n+1 and n² elements respectively and n common elements. A85490

Number of non-congruent solutions of x² + y² + z² + t² == 0 mod n. A240547

Numbers n such that (n(n+1)/2) modulo σ(n) = n. A232538