388821 has 4 divisors (see below), whose sum is σ = 518432. Its totient is φ = 259212.

The previous prime is 388813. The next prime is 388823. The reversal of 388821 is 128883.

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, and also an emirpimes, since its reverse is a distinct semiprime: 128883 = 3 ⋅42961.

It is not a de Polignac number, because 388821 - 2³ = 388813 is a prime.

It is a D-number.

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 (388823) 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, 64801 + ... + 64806.

It is an arithmetic number, because the mean of its divisors is an integer number (129608).

2³⁸⁸⁸²¹ is an apocalyptic number.

It is an amenable number.

388821 is a deficient number, since it is larger than the sum of its proper divisors (129611).

388821 is a wasteful number, since it uses less digits than its factorization.

388821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129610.

The product of its digits is 3072, while the sum is 30.

The square root of 388821 is about 623.5551298803. Note that the first 3 decimals coincide. The cubic root of 388821 is about 72.9877379792.

It can be divided in two parts, 38882 and 1, that added together give a palindrome (38883).

The spelling of 388821 in words is "three hundred eighty-eight thousand, eight hundred twenty-one".