Properties of the Number 4991

Four Thousand Nine Hundred Ninety-One

Basics

Value: 4990 → 4991 → 4992

Parity: odd

Prime: No

Previous Prime: 4987

Next Prime: 4993

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 7 × 23 × 31

Divisors: 1, 7, 23, 31, 161, 217, 713, 4991

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 1001101111111

Octal: 11577

Duodecimal: 2A7B

Hexadecimal: 137f

Square: 24910081

Square Root: 70.64700984472024

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

Centered octahedral numbers (crystal ball sequence for cubic lattice). A1845

a(n) = C(n,1) + C(n,2) + C(n,3), or n*(n² + 5)/6. A4006

Number of partitions of n such that no part is a sum of two or more other parts. A237667

Lucas-Carmichael numbers: squarefree composite numbers k such that p | k => p+1 | k+1. A6972

Lucas-Carmichael numbers with 3 prime factors. A216925

G.f. satisfies: A(x) = 1/(1 + x·A(x²)) and also the continued fraction: 1 + x·A(x³) = [1; 1/x, 1/x², 1/x⁴, 1/x⁸, ..., 1/x^{2^(n-1}), ...]. A101912

A sequence of asymptotic density ζ(8) - 1, where ζ is the Riemann ζ function. A143034

Quasi-Carmichael numbers to exactly two bases. A257752

a(n) = ∑_d∣n σ(n/d)*d⁴. A27848

T(n,k)=Number of nXk 0..1 arrays with rows and columns in lexicographic nondecreasing order but with exactly two mistakes. A278325