Properties of the Number 2805

Two Thousand Eight Hundred Five

Basics

Value: 2804 → 2805 → 2806

Parity: odd

Prime: No

Previous Prime: 2803

Next Prime: 2819

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 3 × 5 × 11 × 17

Divisors: 1, 3, 5, 11, 15, 17, 33, 51, 55, 85

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101011110101

Octal: 5365

Duodecimal: 1759

Hexadecimal: af5

Square: 7868025

Square Root: 52.96225070746144

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

5 times triangular numbers: a(n) = 5·n*(n+1)/2. A28895

Preperiod (or threshold) of orbit of Post's {00, 1101} tag system applied to the word (100)ⁿ, or -1 if this word has an unbounded trajectory. A284119

Numbers n such that the decimal expansions of both n and n² have 0 as smallest digit and 8 as largest digit. A256708

a(n) = (2·n+5)*(2·n+1). A78371

Second numbers F = a(n) of two non-consecutive numbers (E, F) different from (C, D) = (A352222(n), A352223(n)), such that the sums of their cubes are equal to centered cube numbers and to at least one other sum of two cubes, i.e. A = B³ + (B+1)³ = C³ + D³ = E³ + F³. A352225

List of binary palindromes of even length (written in base 10). A48701

Irregular triangle read by rows where T(n,k) is the number of simple graphs covering n vertices with exactly k triangles, 0 <= k <= binomial(n,3). A372167

Smallest order of cyclotomic polynomial containing n or -n as a coefficient. A13594

a(n) = A019565(A005187(n)). A283475

Numerator of coefficients of Euler polynomials (rising powers). A60096