388640988 has 18 divisors (see below), whose sum is σ = 982398144. Its totient is φ = 129546984.

The previous prime is 388640983. The next prime is 388641023. The reversal of 388640988 is 889046883.

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×388640988² = 302083635107232288, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (388640981) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5397756 + ... + 5397827.

Almost surely, 2^388640988 is an apocalyptic number.

It is an amenable number.

388640988 is an abundant number, since it is smaller than the sum of its proper divisors (593757156).

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

388640988 is a wasteful number, since it uses less digits than its factorization.

388640988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10795593 (or 10795588 counting only the distinct ones).

The product of its (nonzero) digits is 2654208, while the sum is 54.

The square root of 388640988 is about 19713.9795069387. The cubic root of 388640988 is about 729.7647255818.

The spelling of 388640988 in words is "three hundred eighty-eight million, six hundred forty thousand, nine hundred eighty-eight".