Properties of the Number 21690

Twenty-One Thousand Six Hundred Ninety

Basics

Value: 21689 → 21690 → 21691

Parity: even

Prime: No

Previous Prime: 21683

Next Prime: 21701

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 2 × 3 ² × 5 × 241

Divisors: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010010111010

Octal: 52272

Duodecimal: 10676

Hexadecimal: 54ba

Square: 470456100

Square Root: 147.27525250360293

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

Total number of parts in all partitions of n plus the sum of largest parts in all partitions of n plus the number of partitions of n plus n. A225610

Triangle read by rows: T(n,k) is the number of rooted toroidal maps with n edges and k faces and without separating cycles or isthmuses, n >= 2, k = 1..n-1. A343090

Number of rooted toroidal maps with 2 faces and n vertices and without separating cycles or isthmuses. A6422

Numerators of continued fraction convergents to sqrt(905). A42748

Low-temperature series for magnetization in zero-field 3-state Potts model on cubic lattice. A7270

Numbers k for which φ(k) = φ(k''), where φ is the Euler totient function (A000010) and k'' the second arithmetic derivative of k (A068346). A352331

Decimal expansion of 1/686. A21690