Properties of the Number 81901

Eighty-One Thousand Nine Hundred One

Basics

Value: 81900 → 81901 → 81902

Parity: odd

Prime: Yes

Previous Prime: 81899

Next Prime: 81919

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 81901

Divisors: 1, 81901

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10011111111101101

Octal: 237755

Duodecimal: 3B491

Hexadecimal: 13fed

Square: 6707773801

Square Root: 286.1835075611451

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

Apéry-like numbers for the constant e: a(n) = 1/(n-1)!*∑_{k = 0..n+1} (-1)^k*C(n+1,k)*(2·n-k)! for n >= 1. A143413

a(n) = n·a(n-1) + (n-4)*a(n-2), a(2) = 0, a(3) = 1. A1909

Square array A(n,k), n>=1, k>=1, read by antidiagonals: A(n,k) = Fibonacci rabbit sequence number n coded in base k. A144287

Primes which can be expressed as sum of distinct powers of 5. A77719

Table T(n,k) giving number of ways of obtaining exactly 0 correct answers on an (n,k)-matching problem (1 <= k <= n). A76731

a(n) = (1/n!)*A023043(n). A94795

Denominators of "Farey fraction" approximations to e. A119015

Number of terms in n-th derivative of a function composed with itself 8 times. A24208

Triangular array formed from successive differences of factorial numbers, then with factorials removed. A60475

Primes of the form x² + 5·y², where·and y=x+1 are consecutive natural numbers. A176608