Properties of the Number 1825

One Thousand Eight Hundred Twenty-Five

Basics

Value: 1824 → 1825 → 1826

Parity: odd

Prime: No

Previous Prime: 1823

Next Prime: 1831

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 5 ² × 73

Divisors: 1, 5, 25, 73, 365, 1825

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11100100001

Octal: 3441

Duodecimal: 1081

Hexadecimal: 721

Square: 3330625

Square Root: 42.720018726587654

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

Numbers k such that (8·10^k + 49)/3 is prime. A270890

Octagonal numbers: n*(3·n-2). Also called star numbers. A567

Generalized octagonal numbers: k*(3·k-2), k=0, +- 1, +- 2, +-3, ... A1082

Odd numbers of the form p^1+4k * r², where p is prime of the form 1+4m, r > 1, and gcd(p,r) = 1. (Euler's criteria for odd perfect numbers). A228058

Triangular numbers plus quarter squares: n*(n+1)/2 + floor(n²/4) (i.e., A000217(n) + A002620(n)). A6578

Number of divisors of nⁿ, or of A000312(n). A62319

Numbers m that are the hypotenuse of exactly 7 distinct integer-sided right triangles, i.e., m² can be written as a sum of two squares in 7 ways. A97101

Pseudoprimes to base 7. A5938

a(n) = n*(11·n² - 5)/6. A4467

Sum of odd numbers in range 10·n to 10·n+9. A53742