388944821 has 4 divisors (see below), whose sum is σ = 390643500. Its totient is φ = 387246144.

The previous prime is 388944799. The next prime is 388944823. The reversal of 388944821 is 128449883.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 128449883 = 433 ⋅296651.

It can be written as a sum of positive squares in 2 ways, for example, as 310816900 + 78127921 = 17630^2 + 8839^2 .

It is a cyclic number.

It is not a de Polignac number, because 388944821 - 2¹⁴ = 388928437 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 (388944823) 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, 848996 + ... + 849453.

It is an arithmetic number, because the mean of its divisors is an integer number (97660875).

Almost surely, 2^388944821 is an apocalyptic number.

It is an amenable number.

388944821 is a deficient number, since it is larger than the sum of its proper divisors (1698679).

388944821 is a wasteful number, since it uses less digits than its factorization.

388944821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1698678.

The product of its digits is 442368, while the sum is 47.

The square root of 388944821 is about 19721.6840305284. The cubic root of 388944821 is about 729.9548486492.

The spelling of 388944821 in words is "three hundred eighty-eight million, nine hundred forty-four thousand, eight hundred twenty-one".