Properties of the Number 20866

Twenty Thousand Eight Hundred Sixty-Six

Basics

Value: 20865 → 20866 → 20867

Parity: even

Prime: No

Previous Prime: 20857

Next Prime: 20873

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 2 × 10433

Divisors: 1, 2, 10433, 20866

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000110000010

Octal: 50602

Duodecimal: 100AA

Hexadecimal: 5182

Square: 435389956

Square Root: 144.4506836259351

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

Numbers k that divide the (right) concatenation of all numbers <= k written in base 2 (most significant digit on left). A29447

Numbers k that are the products of two distinct primes such that 2·k-1, 4·k-3, 8·k-7, 16·k-15 and 32·k-31 are also products of two distinct primes. A177214

Apply partial sum operator twice to sequence of squares of the first n primes. A157492

Number of compositions of n into distinct parts with exactly one descent. A241720

Ordered sequence of distinct terms of the form floor(exp(i) * floor(exp(j))), i,j >= 0. A22765

Expansion of (2+2·x)/(1-8·x-25·x²). A155542

Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 214", based on the 5-celled von Neumann neighborhood. A270907

Number of nX4 0..1 arrays with every element unequal to 0, 1, 4 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. A318541

Number of admissible mesa sets among Stirling permutations of order n. A363582

T(n,k)=Number of nXk 0..1 arrays with every element unequal to 0, 1, 4 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. A318545