Properties of the Number 1985

One Thousand Nine Hundred Eighty-Five

Basics

Value: 1984 → 1985 → 1986

Parity: odd

Prime: No

Previous Prime: 1979

Next Prime: 1987

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 5 × 397

Divisors: 1, 5, 397, 1985

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11111000001

Octal: 3701

Duodecimal: 1195

Hexadecimal: 7c1

Square: 3940225

Square Root: 44.553338819890925

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

Centered square numbers: a(n) = 2·n*(n+1)+1. Sums of two consecutive squares. Also, consider all Pythagorean triples (X, Y, Z=Y+1) ordered by increasing Z; then sequence gives Z values. A1844

Number of 3 X n binary arrays with a path of adjacent 1's from top row to bottom row. A69361

Odd numbers not of form p + 2^k (de Polignac numbers). A6285

a(n) = 8·n² - 4·n + 1. A80856

a(n) = 2²ⁿ⁺¹ - 2ⁿ⁺¹ + 1. A92440

Number of partitions of n such that number of parts is equal to the sum of parts counted without multiplicities. A114638

Expansion of (1-x)/(1 - 3·x + x²)². A1870

Partial sums of the squarefree numbers, A005117. A173143

Number of integer partitions of n such that more than one set can be obtained by choosing a different divisor of each part. A370803

Triangular array T(n,k), read by rows: coefficients of strong divisibility sequence of polynomials p(1,x) = 1, p(2,x) = 1 + 3·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. A367208