Properties of the Number 21872

Twenty-One Thousand Eight Hundred Seventy-Two

Basics

Value: 21871 → 21872 → 21873

Parity: even

Prime: No

Previous Prime: 21871

Next Prime: 21881

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 2 ⁴ × 1367

Divisors: 1, 2, 4, 8, 16, 1367, 2734, 5468, 10936, 21872

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010101110000

Octal: 52560

Duodecimal: 107A8

Hexadecimal: 5570

Square: 478384384

Square Root: 147.8918523786892

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 2n whose half-alternating sum is 0. A357641

a(n) = 3·a(n-1) - 2·a(n-2) - a(n-3) + a(n-4) with n>3, a(0)=1, a(1)=2, a(2)=3, a(3)=6. A131269

a(n) = [xⁿ] ∏_k=1..n 1/(1 + x^k)^n-k+1. A303174

Number of distinct values of |product(A) - product(B)| where A and B are a partition of {1,2,...,n}. A263292

Numbers k such that 90·R_k + 7 is prime, where R_k = 11...1 is the repunit (A002275) of length k. A56662

Number of points on surface of dodecahedron: a(n) = 30·n² + 2 for n > 0. A5903

Fixed points in A097465. A352096

Number of nondecreasing -n..n vectors of length 3 whose dot product with some nonincreasing -n..n vector equals 3. A226400

Numbers equal to the arithmetic derivative of their Euler totient function. A248815

a(n) = n! [xⁿ] exp(2·x)*(y·sinh(x·y) + cosh(x·y)) and y = sqrt(x). A335537