Properties of the Number 21195

Twenty-One Thousand One Hundred Ninety-Five

Basics

Value: 21194 → 21195 → 21196

Parity: odd

Prime: No

Previous Prime: 21193

Next Prime: 21211

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ³ × 5 × 157

Divisors: 1, 3, 5, 9, 15, 27, 45, 135, 157, 471

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101001011001011

Octal: 51313

Duodecimal: 10323

Hexadecimal: 52cb

Square: 449228025

Square Root: 145.58502670261115

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

a(n) = n³ - n² + n - 1 = (n-1) * (n² + 1). A62158

Number of partitions of n having an ordering of parts in which no parts of equal parity are adjacent and the first and last terms have the same parity. A239833

T(n,k)=Number of ways to reciprocally link elements of an nXk array either to themselves or to exactly two king-move neighbors, without consecutive collinear links. A220718

Numbers n such that n through n+5 have the same number of distinct prime factors. A45934

Numbers n such that n through n+6 are divisible by the same number of distinct primes. A45935

G.f.: A(x) = (A₁)³ where A₁ = 1 + x*(A₂)³; A₂ = 1 + x²*(A₃)³; A₃ = 1 + x³*(A₄)³; ... A_n = 1 + xⁿ*(A_n+1)³ for n>=1. A132331

Exponential Riordan array (e^x, x·A000108(x)). A185946

Deficient numbers n having a companion m > n such that σ(n)/n = σ(m)/m. A212608

Number of ways to reciprocally link elements of an n X 3 array either to themselves or to exactly two king-move neighbors, without consecutive collinear links. A220714

Number of ways to reciprocally link elements of an nX5 array either to themselves or to exactly two king-move neighbors, without consecutive collinear links. A220716