Properties of the Number 21280

Twenty-One Thousand Two Hundred Eighty

Basics

Value: 21279 → 21280 → 21281

Parity: even

Prime: No

Previous Prime: 21277

Next Prime: 21283

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 2 ⁵ × 5 × 7 × 19

Divisors: 1, 2, 4, 5, 7, 8, 10, 14, 16, 19

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001100100000

Octal: 51440

Duodecimal: 10394

Hexadecimal: 5320

Square: 452838400

Square Root: 145.87666023048376

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 reduced words of length n in the Weyl group D₇. A162210

Number of 3 X n Latin rectangles in which the first row is in order. A186

a(n) = n*(n+2)*(n-2)/3. A77415

Number of ways to change three non-identical letters in the word aabbccdd..., where there are n types of letters. A102860

Numbers k such that σ (x) = k has exactly 11 solutions. A60678

Lesser of amicable pair m < n defined by t(n) = m and t(m) = n where t(n) = ψ(n) - n and ψ(n) = A001615(n) is the Dedekind ψ function. A323329

Expansion of g.f. 1/((1 - 4·x)*(1 - 6·x)). A16149

T(n,k)=Number of nXk binary arrays with every element equal to either the sum mod 2 of its vertical neighbors or the sum mod 2 of its horizontal neighbors. A183474

5th binomial transform of (0,1,0,1,...), A000035. A81199

Numbers of the form p⁵*q·r*s where p, q, r, and s are distinct primes. A179704