Properties of the Number 19871

Nineteen Thousand Eight Hundred Seventy-One

Basics

Value: 19870 → 19871 → 19872

Parity: odd

Prime: No

Previous Prime: 19867

Next Prime: 19889

Digit Sum: 26

Digital Root: 8

Palindrome: No

Factorization: 31 × 641

Divisors: 1, 31, 641, 19871

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100110110011111

Octal: 46637

Duodecimal: B5BB

Hexadecimal: 4d9f

Square: 394856641

Square Root: 140.9645345468143

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

Octahedral numbers: a(n) = n*(2·n² + 1)/3. A5900

a(n) = (2·n - 1)*(8·n² - 8·n + 3)/3. A63496

Number of partitions p = [x(1), ..., x(k)], where x(1) >= x(2) >= ... >= x(k), of n such that max(x(i) - x(i-1)) > number of parts of p. A241832

Indices of record values in A228098. A230777

Partial sums of the odd triangular numbers (A014493). A352116

First of three consecutive Ulam numbers (A002858) in arithmetic progression with difference 22. A68856

Semiprimes of the form (2·n³+n)/3. A245232

Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 201", based on the 5-celled von Neumann neighborhood. A279807

a(n) is the least k such that there are exactly n primes between prime(k) + 1 and floor(prime(k + 1)²/prime(k)) (inclusive) or 0 if no such k exists. A344582

Decimal expansion of sine of 62 degrees. A19871