Properties of the Number 20841

Twenty Thousand Eight Hundred Forty-One

Basics

Value: 20840 → 20841 → 20842

Parity: odd

Prime: No

Previous Prime: 20809

Next Prime: 20849

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 3 × 6947

Divisors: 1, 3, 6947, 20841

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000101101001

Octal: 50551

Duodecimal: 10089

Hexadecimal: 5169

Square: 434347281

Square Root: 144.3641229668923

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

Numbers k that divide the (right) concatenation of all numbers <= k written in base 2 (most significant digit on left). A29447

a(n) = number of m such that A080737(m) <= 2n. A80740

Relative of Hofstadter Q-sequence: a(n) = max(0, n+20830) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 0. A283887

Form the difference table of the sequence {2^k*k!}, then divide k-th column entries by 2^k*k!. Array read by ascending antidiagonals, T(n, k) for n, k >= 0. A143410

Main diagonal of A143410. A143412

a(n) = 12·n² - 8·n + 9. A167585

Base-10 version of A038103 interpreted as base 3. A350573

Number of weighted voting procedures. A5256

Row sums of A273751. A274248

Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 80 ones. A31848