Properties of the Number 805

Eight Hundred Five

Basics

Value: 804 → 805 → 806

Parity: odd

Prime: No

Previous Prime: 797

Next Prime: 809

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 5 × 7 × 23

Divisors: 1, 5, 7, 23, 35, 115, 161, 805

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 1100100101

Octal: 1445

Duodecimal: 571

Hexadecimal: 325

Square: 648025

Square Root: 28.372521918222215

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

Generalized pentagonal numbers: m*(3·m - 1)/2, m = 0, +-1, +-2, +-3, .... A1318

Second pentagonal numbers: a(n) = n*(3·n + 1)/2. A5449

Number of partitions of n into distinct parts such that number of parts is odd. A67659

Number of partitions of n into nonprime parts. A2095

Number of partitions of n into distinct parts such that number of parts is even. A67661

Number of strict integer partitions of n with integer median. A359907

a(n) is the least k such that 4^k mod k = n. A119678

a(n) = (prime(n)² - 1)/24. A24702

Numbers n such that the number of squarefree numbers between prime(n) and prime(n+1) = prime(n+1)-prime(n)-1. A68361

Sum of all aliquot divisors of all positive integers <= n. A153485