Properties of the Number 381

Three Hundred Eighty-One

Basics

Value: 380 → 381 → 382

Parity: odd

Prime: No

Previous Prime: 379

Next Prime: 383

Digit Sum: 12

Digital Root: 3

Palindrome: No

Factorization: 3 × 127

Divisors: 1, 3, 127, 381

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101111101

Octal: 575

Duodecimal: 279

Hexadecimal: 17d

Square: 145161

Square Root: 19.519221295943137

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

Sum of the first n primes. A7504

Numbers k such that (68·10^k + 7)/3 is prime. A270613

Central polygonal numbers: a(n) = n² - n + 1. A2061

Binary palindromes: numbers whose binary expansion is palindromic. A6995

Number of partitions of n in which the number of parts divides n. A67538

Numbers k such that k and k+1 have the same number of divisors. A5237

a(n) = 10·n + 1. A17281

Number of subsets of {1, 2, ..., n} such that no member is a sum of distinct other members. A151897

Sum of divisors of square numbers. A65764

Quarter-squares plus 1 (that is, a(n) = A002620(n) + 1). A33638