388997640 has 320 divisors, whose sum is σ = 1411344000. Its totient is φ = 95800320.

The previous prime is 388997633. The next prime is 388997647. The reversal of 388997640 is 46799883.

It is an interprime number because it is at equal distance from previous prime (388997633) and next prime (388997647).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (388997647) by changing a digit.

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 79 ways as a sum of consecutive naturals, for example, 4370716 + ... + 4370804.

It is an arithmetic number, because the mean of its divisors is an integer number (4410450).

Almost surely, 2^388997640 is an apocalyptic number.

388997640 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 388997640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (705672000).

388997640 is an abundant number, since it is smaller than the sum of its proper divisors (1022346360).

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

388997640 is a wasteful number, since it uses less digits than its factorization.

388997640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 54.

The square root of 388997640 is about 19723.0230948503. The cubic root of 388997640 is about 729.9878899599.

The spelling of 388997640 in words is "three hundred eighty-eight million, nine hundred ninety-seven thousand, six hundred forty".