381845 has 4 divisors (see below), whose sum is σ = 458220. Its totient is φ = 305472.

The previous prime is 381841. The next prime is 381853. The reversal of 381845 is 548183.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 548183 = 277 ⋅1979.

It can be written as a sum of positive squares in 2 ways, for example, as 117649 + 264196 = 343^2 + 514^2 .

It is a cyclic number.

It is not a de Polignac number, because 381845 - 2² = 381841 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (381841) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 38180 + ... + 38189.

It is an arithmetic number, because the mean of its divisors is an integer number (114555).

2³⁸¹⁸⁴⁵ is an apocalyptic number.

It is an amenable number.

381845 is a deficient number, since it is larger than the sum of its proper divisors (76375).

381845 is an equidigital number, since it uses as much as digits as its factorization.

381845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76374.

The product of its digits is 3840, while the sum is 29.

The square root of 381845 is about 617.9360808368. The cubic root of 381845 is about 72.5485999942.

The spelling of 381845 in words is "three hundred eighty-one thousand, eight hundred forty-five".