Properties of the Number 21865

Twenty-One Thousand Eight Hundred Sixty-Five

Basics

Value: 21864 → 21865 → 21866

Parity: odd

Prime: No

Previous Prime: 21863

Next Prime: 21871

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 5 × 4373

Divisors: 1, 5, 4373, 21865

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010101101001

Octal: 52551

Duodecimal: 107A1

Hexadecimal: 5569

Square: 478078225

Square Root: 147.8681845428556

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

Starts of runs of 4 consecutive integers that are greedy Jacobsthal-Niven numbers (A364379). A364382

a(n) = 26·n² - 1. A158551

a(n) = prime(1³) + prime(2³) + prime(3³) + ... + prime(n³). A109789

a(n) = 841·n - 1. A158402

a(n) = A000081(n+1) - 2·A000081(n). A74797

Minimal peaks in digital expansions of π: positions of peaks equal to 1. A105275

a(1) = 1, a(2) = 2; for n > 2, a(n) is the smallest positive number that has not appeared that shares a factor with both the largest and second largest value of all previous terms. A351626

Decimal expansion of 1/861. A21865