388931638 has 4 divisors (see below), whose sum is σ = 583397460. Its totient is φ = 194465818.

The previous prime is 388931579. The next prime is 388931639. The reversal of 388931638 is 836139883.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 388931591 and 388931600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (388931639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97232908 + ... + 97232911.

It is an arithmetic number, because the mean of its divisors is an integer number (145849365).

Almost surely, 2^388931638 is an apocalyptic number.

388931638 is a deficient number, since it is larger than the sum of its proper divisors (194465822).

388931638 is a wasteful number, since it uses less digits than its factorization.

388931638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194465821.

The product of its digits is 746496, while the sum is 49.

The square root of 388931638 is about 19721.3498016743. The cubic root of 388931638 is about 729.9466014609.

The spelling of 388931638 in words is "three hundred eighty-eight million, nine hundred thirty-one thousand, six hundred thirty-eight".