381856817 has 4 divisors (see below), whose sum is σ = 382027380. Its totient is φ = 381686256.

The previous prime is 381856799. The next prime is 381856829. The reversal of 381856817 is 718658183.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 718658183 = 43 ⋅16712981.

It can be written as a sum of positive squares in 2 ways, for example, as 57820816 + 324036001 = 7604^2 + 18001^2 .

It is a cyclic number.

It is not a de Polignac number, because 381856817 - 2⁸ = 381856561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (381856877) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81878 + ... + 86415.

It is an arithmetic number, because the mean of its divisors is an integer number (95506845).

Almost surely, 2^381856817 is an apocalyptic number.

It is an amenable number.

381856817 is a deficient number, since it is larger than the sum of its proper divisors (170563).

381856817 is a wasteful number, since it uses less digits than its factorization.

381856817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170562.

The product of its digits is 322560, while the sum is 47.

The square root of 381856817 is about 19541.1570025933. The cubic root of 381856817 is about 725.4934837640.

The spelling of 381856817 in words is "three hundred eighty-one million, eight hundred fifty-six thousand, eight hundred seventeen".