Properties of the Number -2025

Twenty-Five

Basics

Value: -2026 → -2025 → -2024

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 9

Digital Root: 9

Palindrome: No

Factorization: 3 ⁴ × 5 ²

Divisors: 1, 3, 5, 9, 15, 25, 27, 45, 75, 81

Polygonal

Triangular: No

Square: Yes

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -11111101001

Octal: -3751

Duodecimal: -1209

Hexadecimal: -7e9

Square: 4100625

Square Root: 45

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: Yes

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

Difference between sums of quadratic residues and non-residues modulo n (residues are not necessarily coprime to n). A255644

Determinants of the Hankel matrices for the period-doubling sequence A035263. A265025

McKay-Thompson series of class 14a for Monster. A58505

Expansion of (1-x) / (1+x²+2·x³). A78033

Determinant of the n X n tridiagonal matrix M with the elements on the diagonals equal to 1, except M(n,n-1)=M(n-1,n)=n. A80322

a(n) = (-1)^n-3*binomial(n,3) - 1. A216414

Alternating sum of centered 25-gonal numbers. A270693

Triangle read by rows: T[n, m] = Sum[m³ - 3·m²*k + 3·m*k² - k³, {k, 0, n - 1}] + m⁴. A121721

The squares: a(n) = n². A290

Odd squares: a(n) = (2n+1)². Also centered octagonal numbers. A16754