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Properties of the Number 21128

Twenty-One Thousand One Hundred Twenty-Eight

Basics

Value: 21127 → 21128 → 21129

Parity: even

Prime: No

Previous Prime: 21121

Next Prime: 21139

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 2 3 × 19 × 139

Divisors: 1, 2, 4, 8, 19, 38, 76, 139, 152, 278

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

8509 Try Today's Challenge

Representations

Binary: 101001010001000

Octal: 51210

Duodecimal: 10288

Hexadecimal: 5288

Square: 446392384

Square Root: 145.354738484853

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

Number of n-celled free polyominoes with 1 hole. A57418
Number of ways to split an integer partition of n into contiguous subsequences with weakly increasing sums. A336136
a(n+1) = ∑k=0..floor(n/4) a(k) * a(n-k). A30034
Consider the triangle shown below; sequence contains the concatenation of numbers read at a 45-degree angle upwards with horizontal beginning with the first term of a row. A79826
Satisfies a(n)/A079159(n) = pn, the n-th prime (n>0), a(0)=1. A79161
Number of (6+2)X(n+2) 0..1 arrays with every 3X3 subblock sum of the two sums of the diagonal and antidiagonal minus the two minimums of the central column and central row nondecreasing horizontally, vertically and ne-to-sw antidiagonally. A254912
32-gonal numbers: a(n) = n*(15·n-14). A360436
a(n) = n*(1+3·n+6·n2)/2. A115519
Number of 5-step one or two space at a time bishop's tours on an n X n board summed over all starting positions. A187049
Decimal expansion of 1/124. A21128