Properties of the Number 20669

Twenty Thousand Six Hundred Sixty-Nine

Basics

Value: 20668 → 20669 → 20670

Parity: odd

Prime: No

Previous Prime: 20663

Next Prime: 20681

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 11 × 1879

Divisors: 1, 11, 1879, 20669

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000010111101

Octal: 50275

Duodecimal: BB65

Hexadecimal: 50bd

Square: 427207561

Square Root: 143.76717288727633

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

Number of integer compositions of n whose leaders of strictly increasing runs are distinct. A374687

(L)-sieve transform of A004767 = {3,7,11,15,...,4n-1,...}. A155167

T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with the maximum plus the minimum minus the upper median minus the lower median of every 2X2 subblock equal. A237167

Irregular table read by rows: Place n equally spaced points on the circumference of a circle of radius r and then connect each pair of points with straight lines whose intersections create A007569(n) - n additional points. Draw a circle of radius r around each of the A007569(n) points. T(n,k) is the number of k-sided regions, k>=2, formed from all circle intersections. A374828

a(n) is the number of distinct triangles whose sides do not pass through a grid point and whose vertices are three points of an n X n grid. A372217

n+p(n)+p(p(n)) is a square, where p(n) is the n-th prime. A116011

Number of binary matrices with 3 distinct columns and any number of nonzero rows with n ones in every column and rows in nonincreasing lexicographic order. A331390

Number of (n+1)X(2+1) 0..2 arrays with the maximum plus the minimum minus the upper median minus the lower median of every 2X2 subblock equal. A237161

Number of (n+1)X(4+1) 0..2 arrays with the maximum plus the minimum minus the upper median minus the lower median of every 2X2 subblock equal. A237163

a(n) is the Frobenius number for the set { binomial(m,k), k=1..m-1 } where m = A024619(n). A389479