388921638 has 16 divisors (see below), whose sum is σ = 888963840. Its totient is φ = 111120456.

The previous prime is 388921607. The next prime is 388921669. The reversal of 388921638 is 836129883.

It is an interprime number because it is at equal distance from previous prime (388921607) and next prime (388921669).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4629978 + ... + 4630061.

It is an arithmetic number, because the mean of its divisors is an integer number (55560240).

Almost surely, 2^388921638 is an apocalyptic number.

388921638 is an abundant number, since it is smaller than the sum of its proper divisors (500042202).

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

388921638 is a wasteful number, since it uses less digits than its factorization.

388921638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9260051.

The product of its digits is 497664, while the sum is 48.

The square root of 388921638 is about 19721.0962677028. The cubic root of 388921638 is about 729.9403454098.

The spelling of 388921638 in words is "three hundred eighty-eight million, nine hundred twenty-one thousand, six hundred thirty-eight".