Properties of the Number 813

Eight Hundred Thirteen

Basics

Value: 812 → 813 → 814

Parity: odd

Prime: No

Previous Prime: 811

Next Prime: 821

Digit Sum: 12

Digital Root: 3

Palindrome: No

Factorization: 3 × 271

Divisors: 1, 3, 271, 813

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2730 Try Today's Challenge

Representations

Binary: 1100101101

Octal: 1455

Duodecimal: 579

Hexadecimal: 32d

Square: 660969

Square Root: 28.513154858766505

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

Central polygonal numbers: a(n) = n² - n + 1. A2061

Triangle read by rows: T(n,k) is the number of compositions of n into nonzero parts with k parts directly followed by a different part, n>=0, 0<=k<=A004523(n-1). A238279

Indices k such that (1/3)*(prime(k)+prime(k+1)+prime(k+2)) is a prime. A64113

a(n) = ∑_k=1..n n/gcd(n,k). A57660

Quarter-squares plus 1 (that is, a(n) = A002620(n) + 1). A33638

Number of strict integer partitions of n with pairwise indivisible parts. A303362

a(n) = 4·n² - 6·n + 3. A54569

Coordination sequence for 3D uniform tiling formed by stacking parallel layers of the 3⁴.6 2D tiling (cf. A250120). A299254

a(n) = a(n-1) + a(floor(n/2)), a(1) = 1. A33485

a(n) = least m such that if a/b < c/d where a,b,c,d are integers in [0,n], then a/b < k/m < c/d for some integer k. A1000