388664021 has 8 divisors (see below), whose sum is σ = 399426360. Its totient is φ = 377915328.

The previous prime is 388663973. The next prime is 388664027. The reversal of 388664021 is 120466883.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 78411025 + 310252996 = 8855^2 + 17614^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-388664021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (388664027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86195 + ... + 90591.

It is an arithmetic number, because the mean of its divisors is an integer number (49928295).

Almost surely, 2^388664021 is an apocalyptic number.

It is an amenable number.

388664021 is a deficient number, since it is larger than the sum of its proper divisors (10762339).

388664021 is a wasteful number, since it uses less digits than its factorization.

388664021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6823.

The product of its (nonzero) digits is 55296, while the sum is 38.

The square root of 388664021 is about 19714.5636776470. The cubic root of 388664021 is about 729.7791419193.

The spelling of 388664021 in words is "three hundred eighty-eight million, six hundred sixty-four thousand, twenty-one".