Properties of the Number 1681

One Thousand Six Hundred Eighty-One

Basics

Value: 1680 → 1681 → 1682

Parity: odd

Prime: No

Previous Prime: 1669

Next Prime: 1693

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 41 ²

Divisors: 1, 41, 1681

Polygonal

Triangular: No

Square: Yes

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11010010001

Octal: 3221

Duodecimal: B81

Hexadecimal: 691

Square: 2825761

Square Root: 41

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

The squares: a(n) = n². A290

Perfect powers: m^k where m > 0 and k >= 2. A1597

Squares of primes. A1248

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

1 and the prime powers p^m where m >= 2, thus excluding the primes. A25475

Prime powers p^e where p is a prime and e >= 2 (prime powers without the primes or 1). A246547

Number of separable partitions of n; see Comments. A325534

Number of partitions of n having an integer median. A325347

a(n) = 2·n² - 1. A56220

Numbers whose sum of divisors is prime. A23194