Properties of the Number 2820

Two Thousand Eight Hundred Twenty

Basics

Value: 2819 → 2820 → 2821

Parity: even

Prime: No

Previous Prime: 2819

Next Prime: 2833

Digit Sum: 12

Digital Root: 3

Palindrome: No

Factorization: 2 ² × 3 × 5 × 47

Divisors: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101100000100

Octal: 5404

Duodecimal: 1770

Hexadecimal: b04

Square: 7952400

Square Root: 53.103672189407014

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

Triangle read by rows: T(n,m) (n >= m >= 1) = number of regions (or cells) formed by drawing the line segments connecting any two of the 2*(m+n) perimeter points of an m X n grid of squares. A331452

Multiples of 20 containing a 20 in their decimal representation. A121040

Numbers m such that m and m+1 are consecutive factorial base Niven numbers (A118363). A328205

E-toothpick sequence (see Comments lines for definition). A161328

Numbers k such that k and k+1 are both primorial base Niven numbers (A333426). A333427

Triangular array T(n,k), read by rows: coefficients of strong divisibility sequence of polynomials p(1,x) = 1, p(2,x) = 1 + 4·x, p(n,x) = u·p(n-1,x) + v·p(n-2,x) for n >= 3, where u = p(2,x), v = 1 - x - x². A367209

First numbers E = a(n) of two non-consecutive numbers (E, F) different from (C, D) = (A352222(n), A352223(n)), such that the sums of their cubes are equal to centered cube numbers and to at least one other sum of two cubes, i.e. A = B³ + (B+1)³ = C³ + D³ = E³ + F³. A352224

Generalized pentagonal numbers: a(n) = 12·n + 3·n*(n-1)/2. A151542

Numbers k such that k and k + 1 are both lazy-Lucas-Niven numbers (A351719). A351720

a(n) = n*(3·n + 4). A140676