Properties of the Number 81509

Eighty-One Thousand Five Hundred Nine

Basics

Value: 81508 → 81509 → 81510

Parity: odd

Prime: Yes

Previous Prime: 81463

Next Prime: 81517

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 81509

Divisors: 1, 81509

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10011111001100101

Octal: 237145

Duodecimal: 3B205

Hexadecimal: 13e65

Square: 6643717081

Square Root: 285.49781084975064

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

Smallest prime p such that there is a gap of 2n between p and previous prime. A1632

a(n) is the smallest prime q such that, for the previous prime p and the following prime r, the fraction (r-q)/(q-p) has denominator n in lowest terms. A179234

Primes p such that φ(φ(p-1)+1) = φ(φ(p-2)+1). A271659

Increasing peaks in the prime gap sequence A001632. A86978

Primes at the end of the first-occurrence gaps in A014320. A335367

Discriminants of totally real quintic fields. A23683

Floor-Sqrt transform of Lucas numbers (A000032). A192660

a(0) = 3, then a(n) is the least prime greater than a(n-1) that follows a gap of exactly 2·n. A253899

Smallest prime p such that there is a gap of 2·prime(n) between p and previous prime. A80083

a(n) = least prime P(n) such that P(n)-2·p(n) is prime and P(n+1)>P(n) with p(n)=n-th prime. A115972