Properties of the Number 18991

Eighteen Thousand Nine Hundred Ninety-One

Basics

Value: 18990 → 18991 → 18992

Parity: odd

Prime: No

Previous Prime: 18979

Next Prime: 19001

Digit Sum: 28

Digital Root: 1

Palindrome: No

Factorization: 7 × 2713

Divisors: 1, 7, 2713, 18991

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100101000101111

Octal: 45057

Duodecimal: ABA7

Hexadecimal: 4a2f

Square: 360658081

Square Root: 137.8078372227066

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

Expansion of 1/(1 + ∑_k>=1 k² * x^k). A316087

Numbers k such that k*(k+2) is a palindrome. A28503

Numbers k such that (k*(k+1)*(k+2)) / (k+(k+1)+(k+2)) is a palindrome. A32789

Numbers k such that A084937(3k) > A084937(3k+1). A249689

a(1) = 1; for m >= 2, a(n) = a(n-1) + floor(a(n-1)/(n-1)) + 2. A33156

Cycle class sequence c(2n) (the number of true cycles of length 2n in which a certain node is included) for zeolite ATV = AlPO4-25 [Al12P12O48] starting with a T1 atom. A18991