388909 has 4 divisors (see below), whose sum is σ = 411804. Its totient is φ = 366016.

The previous prime is 388903. The next prime is 388931. The reversal of 388909 is 909883.

388909 = 90² + 91² + ... + 123².

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 909883 = 13 ⋅69991.

It can be written as a sum of positive squares in 2 ways, for example, as 324900 + 64009 = 570^2 + 253^2 .

It is a cyclic number.

It is not a de Polignac number, because 388909 - 2³ = 388901 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 (388901) 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 3 ways as a sum of consecutive naturals, for example, 11422 + ... + 11455.

It is an arithmetic number, because the mean of its divisors is an integer number (102951).

2³⁸⁸⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

388909 is a deficient number, since it is larger than the sum of its proper divisors (22895).

388909 is a wasteful number, since it uses less digits than its factorization.

388909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22894.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 388909 is about 623.6256890155. The cubic root of 388909 is about 72.9932438859.

The spelling of 388909 in words is "three hundred eighty-eight thousand, nine hundred nine".