381808138 has 4 divisors (see below), whose sum is σ = 572712210. Its totient is φ = 190904068.

The previous prime is 381808127. The next prime is 381808139. The reversal of 381808138 is 831808183.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 831808183 = 13721 ⋅60623.

It can be written as a sum of positive squares in only one way, i.e., 379743169 + 2064969 = 19487^2 + 1437^2 .

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 self number, because there is not a number n which added to its sum of digits gives 381808138.

It is not an unprimeable number, because it can be changed into a prime (381808139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95452033 + ... + 95452036.

Almost surely, 2^381808138 is an apocalyptic number.

381808138 is a deficient number, since it is larger than the sum of its proper divisors (190904072).

381808138 is a wasteful number, since it uses less digits than its factorization.

381808138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190904071.

The product of its (nonzero) digits is 36864, while the sum is 40.

The square root of 381808138 is about 19539.9114122864. The cubic root of 381808138 is about 725.4626538852.

The spelling of 381808138 in words is "three hundred eighty-one million, eight hundred eight thousand, one hundred thirty-eight".