388931640 has 32 divisors (see below), whose sum is σ = 1166795280. Its totient is φ = 103715072.

The previous prime is 388931639. The next prime is 388931657. The reversal of 388931640 is 46139883.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 388931592 and 388931601.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1620429 + ... + 1620668.

Almost surely, 2^388931640 is an apocalyptic number.

388931640 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

388931640 is an abundant number, since it is smaller than the sum of its proper divisors (777863640).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

388931640 is a wasteful number, since it uses less digits than its factorization.

388931640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3241111 (or 3241107 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 388931640 is about 19721.3498523808. The cubic root of 388931640 is about 729.9466027121.

The spelling of 388931640 in words is "three hundred eighty-eight million, nine hundred thirty-one thousand, six hundred forty".