Properties of the Number -1990

Nine Hundred Ninety

Basics

Value: -1991 → -1990 → -1989

Parity: even

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 2 × 5 × 199

Divisors: 1, 2, 5, 10, 199, 398, 995, 1990

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -11111000110

Octal: -3706

Duodecimal: -119A

Hexadecimal: -7c6

Square: 3960100

Square Root: 44.609416046390926

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

Expansion of ∏_m>=1 (1-m·q^m). A22661

Stella octangula numbers: a(n) = n*(2·n² - 1). A7588

Numbers m such that the Bernoulli number B_m has denominator 66. A51230

Numbers n such that the decimal expansions of both n and n² have 0 as smallest digit and 9 as largest digit. A256709

Number of quanimous subsets of {1..n}, meaning there is more than one set partition with all equal block-sums. A371796

a(n) = floor(n*φ¹¹), where φ is the golden ratio, A001622. A4926

Numbers whose binary indices and prime indices have the same sum. A372427

Numbers where 9 outnumbers any other digit. A292449

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

T(n,k)=Number of 0..k arrays x(0..n+1) of n+2 elements without any interior element greater than both neighbors or less than both neighbors. A200871