Properties of the Number -1861

Eight Hundred Sixty-One

Basics

Value: -1862 → -1861 → -1860

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 1861

Divisors: 1, 1861

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -11101000101

Octal: -3505

Duodecimal: -10B1

Hexadecimal: -745

Square: 3463321

Square Root: 43.139309220245984

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 ψ(x³)³ / (ψ(x)² * ψ(x²)) in powers of·where ψ() is a Ramanujan θ function. A262157

a(n) = numerator of the coefficient c(n) of xⁿ in sqrt(1+x)/∏_k=1..n-1 1 + c(k)*x^k, n = 1, 2, 3, ... A170922

a(n) = 137·n² - 4043·n + 27277. A267706

E.g.f.: ∏_k>=1 (1 - (1 - exp(x))^k). A336097

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

Primes of the form 2x² + 13y². A107132

Primes of the form j² + (j+1)². A27862

Number of partition into distinct parts (a₁, a₂, ... , a_m) (a₁ > a₂ > ... > a_m and ∑_k=1..m a_k = n) such that a1 - a2, a2 - a₃, ... , a_m-1 - a_m, a_m are different. A320348

Primes of the form x² + 45y². A107152

Primes p such that continued fraction of (1 + sqrt(p))/2 has period 15: primes in A146338. A146360