Properties of the Number 72581

Seventy-Two Thousand Five Hundred Eighty-One

Basics

Value: 72580 → 72581 → 72582

Parity: odd

Prime: No

Previous Prime: 72577

Next Prime: 72613

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 181 × 401

Divisors: 1, 181, 401, 72581

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10001101110000101

Octal: 215605

Duodecimal: 36005

Hexadecimal: 11b85

Square: 5268001561

Square Root: 269.40861159213154

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 partitions of n with unimodal run-lengths. A332280

Solutions k of the equation φ(k) = φ(k-1) + φ(k-2). Also known as Phibonacci numbers. A65557

a(n) = p(n+3)-p(n+1), where p(n) = A238825(n). A238826

a(n) = n⁴/2 - n³ + 3·n²/2 - n + 1 = (n² + 1)*(n² - 2·n + 2)/2. A58919

a(n) = a(n-1)+ceiling(a(n-2)/2) with a(0)=0, a(1)=1. A64323

Composite numbers k such that φ(k) = φ(k-1) + φ(k-2). A65572

Sum T(n,k) of the entries in the k-th last blocks of all set partitions of [n]; triangle T(n,k), n>=1, 1<=k<=n, read by rows. A286232

a(n) = a(n-1) + a(n-2) - floor(a(n-2)/2), starting 2,1. A173497

Strong pseudoprimes to base 22. A20248

a(n) = A000040(A072578(n)). A72581