Properties of the Number 11985

Eleven Thousand Nine Hundred Eighty-Five

Basics

Value: 11984 → 11985 → 11986

Parity: odd

Prime: No

Previous Prime: 11981

Next Prime: 11987

Digit Sum: 24

Digital Root: 6

Palindrome: No

Factorization: 3 × 5 × 17 × 47

Divisors: 1, 3, 5, 15, 17, 47, 51, 85, 141, 235

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10111011010001

Octal: 27321

Duodecimal: 6B29

Hexadecimal: 2ed1

Square: 143640225

Square Root: 109.47602477255009

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

Number of ways to partition the (vertex) set {1,2,...,n} into any number of classes and then select some unordered pairs (edges) <a,b> such that a and b are in distinct classes of the partition. A240936

Generalized Stirling number triangle of first kind read by rows: T(n, k) = [x^k] ∏_m=1..n (x - m - r), with r = 5. A51338

Numbers whose sum of divisors is a fourth power. A19422

G.f.: exp( ∑_n>=1 A000204(n)⁵ * xⁿ/n ) where A000204 is the Lucas numbers. A203805

Magic sums of 4 X 4 magic squares composed of squares. A271580

Triangle T(n,k) giving coefficients in expansion of n!*binomial(x-n,n) in powers of x. A54655

a(n) = 4·n³ + 5·n² + 2·n + 1. A204674

Odd n such that 2*φ(n) < n, but there does not exist an even k < n with φ(k) = φ(n). A118700

Primitive elements of A119432. A119433

a(n) = ∑_{k=floor((n+1)/2)..n} T(k,n-k); i.e., a(n) is the n-th diagonal sum of left-justified array T given by A026998. A27010