381865 has 16 divisors (see below), whose sum is σ = 513216. Its totient is φ = 270400.

The previous prime is 381859. The next prime is 381911. The reversal of 381865 is 568183.

It is not a de Polignac number, because 381865 - 2⁷ = 381737 is a prime.

381865 is a lucky number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2850 + ... + 2980.

It is an arithmetic number, because the mean of its divisors is an integer number (32076).

2³⁸¹⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

381865 is a deficient number, since it is larger than the sum of its proper divisors (131351).

381865 is a wasteful number, since it uses less digits than its factorization.

381865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200.

The product of its digits is 5760, while the sum is 31.

The square root of 381865 is about 617.9522635285. The cubic root of 381865 is about 72.5498666047.

It can be divided in two parts, 3818 and 65, that added together give a palindrome (3883).

The spelling of 381865 in words is "three hundred eighty-one thousand, eight hundred sixty-five".