Properties of the Number 9987

Nine Thousand Nine Hundred Eighty-Seven

Basics

Value: 9986 → 9987 → 9988

Parity: odd

Prime: No

Previous Prime: 9973

Next Prime: 10007

Digit Sum: 33

Digital Root: 6

Palindrome: No

Factorization: 3 × 3329

Divisors: 1, 3, 3329, 9987

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10011100000011

Octal: 23403

Duodecimal: 5943

Hexadecimal: 2703

Square: 99740169

Square Root: 99.93497886125758

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) = (-4·n³ + 27·n² - 20·n + 3)/3. A161711

G.f.: ∑_{k >= 1} x^k/(1-x^k)^k+1. A81543

Numbers k such that k, k+2, k+4, k+6, k+8, k+10 are semiprimes. A92128

Numbers k such that k, k+2, k+4, k+6, k+8 are semiprimes. A92127

Numbers with rounded up arithmetic mean of digits = 9. A178369

Consider a number of k digits n = d_k*10^k-1 + d_k-1*10^k-2 + … + d₂*10 + d₁. Sequence lists the numbers n such that σ(n)-n = ∑_i=1..k-1{σ(∑_j=1..i{d_j*10^j-1})} + ∑_i=1..k-1{σ(∑_j=1..i{d_k-j+1*10^i-j})} (see example below). A240902

Values·for records of minima of the positive distance d between an 11th power of a positive integer·and a square of an integer y such that d = x¹³ - y² (x<>k² and y<>k¹³). A179799

Magic sums of 3 X 3 semimagic squares composed of positive triangular numbers. A269060

Composite numbers and 1 which yield a prime whenever a 7 is inserted anywhere in them, including at the beginning or end. A216168

a(n) is the largest n-digit number whose truncation after its first k digits is divisible by the k-th Fibonacci number for k = 1..n. A242809