Properties of the Number 78021

Seventy-Eight Thousand Twenty-One

Basics

Value: 78020 → 78021 → 78022

Parity: odd

Prime: No

Previous Prime: 78017

Next Prime: 78031

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 8669

Divisors: 1, 3, 9, 8669, 26007, 78021

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10011000011000101

Octal: 230305

Duodecimal: 39199

Hexadecimal: 130c5

Square: 6087276441

Square Root: 279.3223943761044

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

G.f. is the polynomial (1-x³) * (1-x⁶) * (1-x⁹) * (1-x¹²) * (1-x¹⁵) * (1-x¹⁸) * (1-x²¹) * (1-x²⁴) / (1-x)⁸. A162596

Number of n X 3 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 1 neighboring 1. A296315

The smallest deficient number that begins a run of at least n consecutive deficient numbers with the same number of prime factors (counted with multiplicity). A377353

Expansion of (1-x)/(1-x+2·x²+x³). A78021

a(n) begins the first chain of 9 consecutive positive integers of h-values with symmetrical gaps about the center, where h(k) is the length of the finite sequence k, f(k), f(f(k)), ...., 1 in the Collatz (or 3x + 1) problem. A268288