381905806 has 4 divisors (see below), whose sum is σ = 572858712. Its totient is φ = 190952902.

The previous prime is 381905803. The next prime is 381905813. The reversal of 381905806 is 608509183.

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: 608509183 = 23 ⋅26456921.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (381905803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95476450 + ... + 95476453.

It is an arithmetic number, because the mean of its divisors is an integer number (143214678).

Almost surely, 2^381905806 is an apocalyptic number.

381905806 is a deficient number, since it is larger than the sum of its proper divisors (190952906).

381905806 is a wasteful number, since it uses less digits than its factorization.

381905806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190952905.

The product of its (nonzero) digits is 51840, while the sum is 40.

The square root of 381905806 is about 19542.4104449784. The cubic root of 381905806 is about 725.5245073300.

The spelling of 381905806 in words is "three hundred eighty-one million, nine hundred five thousand, eight hundred six".