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Properties of the Number 20889

Twenty Thousand Eight Hundred Eighty-Nine

Basics

Value: 20888 → 20889 → 20890

Parity: odd

Prime: No

Previous Prime: 20887

Next Prime: 20897

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 3 2 × 11 × 211

Divisors: 1, 3, 9, 11, 33, 99, 211, 633, 1899, 2321

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000110011001

Octal: 50631

Duodecimal: 10109

Hexadecimal: 5199

Square: 436350321

Square Root: 144.53027364535086

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(0) = 0. For n > 0, smallest non-palindromic number k such that the smallest palindrome in the Reverse and Add! trajectory of k is reached after exactly n iterations. A23109
T(n,k)=Number of nXk 0..2 arrays with no more than floor(nXk/2) elements unequal to at least one horizontal, diagonal or antidiagonal neighbor, with new values introduced in row major 0..2 order. A222573
The number of odd numbers that require n Collatz (3x+1) iterations to reach 1. A176866
Triangle T(n,k), read by rows, giving the numerator of the coefficient of xk in the Boros-Moll polynomial Pn(x) for n >= 0 and 0 <= k <=n. A223549
Number of nX3 0..2 arrays with no more than floor(nX3/2) elements unequal to at least one horizontal, diagonal or antidiagonal neighbor, with new values introduced in row major 0..2 order. A222568
Smallest k such that the smallest palindrome > k in the Reverse and Add! trajectory of k is reached after exactly n iterations. A15994
a(n) = T(2n-1, n-1), T given by A026536. A26545
a(n) = T(n, floor(n/2)), T given by A026536. A26547
Denominators of continued fraction convergents to sqrt(387). A41735
Least number of Reverse-then-add persistence n. A33866