388391021 has 8 divisors (see below), whose sum is σ = 392434944. Its totient is φ = 384367680.

The previous prime is 388390973. The next prime is 388391023. The reversal of 388391021 is 120193883.

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

It is a cyclic number.

It is not a de Polignac number, because 388391021 - 2⁶ = 388390957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (388391023) 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, 34340 + ... + 44226.

It is an arithmetic number, because the mean of its divisors is an integer number (49054368).

Almost surely, 2^388391021 is an apocalyptic number.

It is an amenable number.

388391021 is a deficient number, since it is larger than the sum of its proper divisors (4043923).

388391021 is a wasteful number, since it uses less digits than its factorization.

388391021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10291.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 388391021 is about 19707.6386459667. The cubic root of 388391021 is about 729.6082347776.

The spelling of 388391021 in words is "three hundred eighty-eight million, three hundred ninety-one thousand, twenty-one".