Properties of the Number 2556

Two Thousand Five Hundred Fifty-Six

Basics

Value: 2555 → 2556 → 2557

Parity: even

Prime: No

Previous Prime: 2551

Next Prime: 2557

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 2 ² × 3 ² × 71

Divisors: 1, 2, 3, 4, 6, 9, 12, 18, 36, 71

Polygonal

Triangular: Yes

Square: No

Pentagonal: No

Hexagonal: Yes

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100111111100

Octal: 4774

Duodecimal: 1590

Hexadecimal: 9fc

Square: 6533136

Square Root: 50.556898639058154

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

Hexagonal numbers: a(n) = n*(2·n-1). A384

Numbers obtained by reinterpreting base-2 representation of n in primorial base: a(0) = 0, a(2n) = A276154(a(n)), a(2n+1) = 1 + A276154(a(n)). A276156

Triangular numbers (A000217) with prime indices. A34953

Triangle read by rows: T(n,k) is the number of inequivalent colorings of lone-child-avoiding rooted trees with n colored leaves using exactly k colors. A339645

Sums of twin prime pairs. A54735

e-perfect numbers: numbers k such that the sum of the e-divisors (exponential divisors) of k equals 2·k. A54979

Coreful perfect numbers: numbers k such that csigma(k) = 2·k, where csigma(k) is the sum of the coreful divisors of k (A057723). A307958

Expansion of (-1 + ∏_k>=1 1 / (1 + (-x)^k))⁴. A341243

3 times pentagonal numbers: 3·n*(3·n-1)/2. A62741

Triangle Q, read by rows, such that Q³ transforms column k of Q² into column k+1 of Q², so that column k of Q² equals column 0 of Q^3·k+2, where Q³ denotes the matrix cube of Q. A113381