388694021 has 4 divisors (see below), whose sum is σ = 388993632. Its totient is φ = 388394412.

The previous prime is 388694017. The next prime is 388694029. The reversal of 388694021 is 120496883.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 388694021 - 2² = 388694017 is a prime.

It is a super-2 number, since 2×388694021² = 302166083922296882, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 388694021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (388694029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 147851 + ... + 150456.

It is an arithmetic number, because the mean of its divisors is an integer number (97248408).

Almost surely, 2^388694021 is an apocalyptic number.

It is an amenable number.

388694021 is a deficient number, since it is larger than the sum of its proper divisors (299611).

388694021 is a wasteful number, since it uses less digits than its factorization.

388694021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299610.

The product of its (nonzero) digits is 82944, while the sum is 41.

The square root of 388694021 is about 19715.3245218028. The cubic root of 388694021 is about 729.7979180428.

The spelling of 388694021 in words is "three hundred eighty-eight million, six hundred ninety-four thousand, twenty-one".