Properties of the Number 21731

Twenty-One Thousand Seven Hundred Thirty-One

Basics

Value: 21730 → 21731 → 21732

Parity: odd

Prime: No

Previous Prime: 21727

Next Prime: 21737

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 31 × 701

Divisors: 1, 31, 701, 21731

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010011100011

Octal: 52343

Duodecimal: 106AB

Hexadecimal: 54e3

Square: 472236361

Square Root: 147.4143819306651

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) is the reverse concatenation of divisors of n. A176558

Numbers that are the sum of 11 positive 8th powers. A3389

Numbers that are the sum of 5 positive 9th powers. A3394

Consider a number x. Take the sum of its digits. Repeat the process deleting the first addendum and adding the previous sum. The sequence lists the numbers that after some iterations reach the arithmetic derivative of x. A269312

The Wiener index of the comb-shaped graph |_|_|...|_| with 2n (n>=1) nodes. The Wiener index of a connected graph is the sum of the distances between all unordered pairs of vertices in the graph. A192023

Numbers k of the form (x + y)*(x² + y²) such that (x + y) and (x² + y²) are primes. A349202

a(n) = A176558(A175354(n)) = numbers m as reverse concatenations of divisors of numbers from A175354, where A175354 = numbers k such that reverse concatenations of divisors of k are nonprimes. A176588

a(n) = (n-1)! + 1 mod n³. A301317

Numbers that are the sum of at most 5 positive 9th powers. A4889

Number of (n+5)X9 0..1 matrices with each 6X6 subblock idempotent. A224573