Properties of the Number 11989

Eleven Thousand Nine Hundred Eighty-Nine

Basics

Value: 11988 → 11989 → 11990

Parity: odd

Prime: No

Previous Prime: 11987

Next Prime: 12007

Digit Sum: 28

Digital Root: 1

Palindrome: No

Factorization: 19 × 631

Divisors: 1, 19, 631, 11989

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10111011010101

Octal: 27325

Duodecimal: 6B31

Hexadecimal: 2ed5

Square: 143736121

Square Root: 109.49429208867465

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

Multiples of 19 containing a 19 in their decimal representation. A121039

Centered 18-gonal numbers. A69131

19-gonal (or enneadecagonal) numbers: n(17n-15)/2. A51871

Number of meanders (walks starting at the origin and ending at any altitude >= 0 that may touch but never go below the x-axis) with n steps from {-3,-2,-1,1,2,3}. A278398

a(n) = ∑_d∣n σ(n/d)*d⁴. A27848

At stage 1, start with a unit equilateral equiangular triangle. At each successive stage add 3*(n-1) new triangles around outside with edge-to-edge contacts. Sequence gives number of triangles (regardless of size) at n-th stage. A64412

Sum of all odd-indexed parts minus the sum of all even-indexed parts of all partitions of n, with the parts written in nondecreasing order. A194714

Number of integer partitions of the n-th semiprime into semiprimes. A338902

Numbers k arising in A144929. A144930

Number of perfect matchings in the P₄ X C_n graph. A252054