Properties of the Number 20828

Twenty Thousand Eight Hundred Twenty-Eight

Basics

Value: 20827 → 20828 → 20829

Parity: even

Prime: No

Previous Prime: 20809

Next Prime: 20849

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 2 ² × 41 × 127

Divisors: 1, 2, 4, 41, 82, 127, 164, 254, 508, 5207

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

4823 Try Today's Challenge

Representations

Binary: 101000101011100

Octal: 50534

Duodecimal: 10078

Hexadecimal: 515c

Square: 433805584

Square Root: 144.31909090622764

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(n) = number of partitions of n into an odd number of parts, the least being 2; also a(n+2) = number of partitions of n into an even number of parts, each >=2. A27188

Triangle read by rows: T(n,k) is the number of paths of length n with steps U=(1,1), D=(1,-1) and H=(1,0), starting at (0,0), staying weakly above the x-axis (i.e., left factors of Motzkin paths) and having k peaks (i.e., UDs), 0 <= k <= floor(n/2). A132893

Number of cubic equations ax³ + bx² + cx + d = 0 with integer coefficients |a|,|b|,|c|,|d| <= n, a <> 0, having one real root and two conjugate complex roots. A155193

The largest part summed over all partitions of n in which every integer from the smallest part to the largest part occurs. A117469

Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite EUO = EU-1 Nan[AlnSi112-nO224] starting with a T3 atom. A19122

Numbers obtained from the tribonacci triangle formed by the number of connection points in the paths obtained by Pell walk on the square grid. A378943

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

Decimal expansion of 1/sqrt(71). A20828

G.f.: (P-Q*(sqrt(1-4·x)))/(x*(1-4·x)³) where P=(1-4·x)³*(1-x-x²), Q=1-11·x+39·x²-40·x³-22·x⁴. A217214