Properties of the Number -7421

Four Hundred Twenty-One

Basics

Value: -7422 → -7421 → -7420

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 41 × 181

Divisors: 1, 41, 181, 7421

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -1110011111101

Octal: -16375

Duodecimal: -4365

Hexadecimal: -1cfd

Square: 55071241

Square Root: 86.14522621712709

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

11-gonal (or hendecagonal) numbers: a(n) = n*(9·n-7)/2. A51682

Another sequence of Apery-like numbers for the constant 1/e: a(n) = 1/(n+1)!*∑_{k = 0..n-1} C(n-1,k)*(2·n-k)!. A143415

Ordered hypotenuses of primitive Pythagorean triangles having legs that add up to a square. A88319

Reverse concatenation of distinct digits of all divisors of n in base 10. A256824

a(n) is equal to the rational part (considering of the field Q(sqrt(13))) of the numbers A(n)/sqrt(13), where we have A(n) = ((sqrt(13) - 1)/2)*A(n-1) + A(n-2) + ((3-sqrt(13))/2)*A(n-3), with A(0) = 6, A(1) = sqrt(13) - 1, and A(2) = 11 - sqrt(13). A216486

E.g.f.: exp(x)/(1-x)⁷. A96341

T(n,k)=Number of nXk 0..1 arrays with every element unequal to 1, 2, 3 or 4 king-move adjacent elements, with upper left element zero. A303896

The square root of A100252; the index of the least square number greater than 1 that is also an n-gonal number, or 0 if none exists. A100251

a(n) = 6·n² - 10·n + 5. A136392

Index of A190874 at record terms. A202187