Properties of the Number 1987

One Thousand Nine Hundred Eighty-Seven

Basics

Value: 1986 → 1987 → 1988

Parity: odd

Prime: Yes

Previous Prime: 1979

Next Prime: 1993

Digit Sum: 25

Digital Root: 7

Palindrome: No

Factorization: 1987

Divisors: 1, 1987

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11111000011

Octal: 3703

Duodecimal: 1197

Hexadecimal: 7c3

Square: 3948169

Square Root: 44.57577817604534

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) = ∑_k=1..n k·floor(n/k); also ∑_k=1..n σ(k) where σ(n) = sum of divisors of n (A000203). A24916

Primes p such that the decimal expansion of its base-9 conversion is also prime. A65727

Partial sums of A299274. A299275

Coordination sequence for "ubt" 3D uniform tiling. A299291

Primes of the form m² + 3m + 9, where m can be positive or negative. A5471

First term of strong prime quartets: prime(m+1)-prime(m) > prime(m+2)-prime(m+1) > prime(m+3)-prime(m+2). A54804

Stack polyominoes with square core. A188674

a(n) = 2·n² - 2·n + 3. A97080

Numbers n with property that, reading binary expansion of n from right to left, run lengths strictly increase. A37015

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