388921 has 4 divisors (see below), whose sum is σ = 418852. Its totient is φ = 358992.

The previous prime is 388903. The next prime is 388931. The reversal of 388921 is 129883.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 212521 + 176400 = 461^2 + 420^2 .

It is a cyclic number.

It is not a de Polignac number, because 388921 - 2⁷ = 388793 is a prime.

It is a Duffinian 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, 14946 + ... + 14971.

It is an arithmetic number, because the mean of its divisors is an integer number (104713).

2³⁸⁸⁹²¹ is an apocalyptic number.

It is an amenable number.

388921 is a deficient number, since it is larger than the sum of its proper divisors (29931).

388921 is a wasteful number, since it uses less digits than its factorization.

388921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29930.

The product of its digits is 3456, while the sum is 31.

The square root of 388921 is about 623.6353100972. The cubic root of 388921 is about 72.9939946270.

The spelling of 388921 in words is "three hundred eighty-eight thousand, nine hundred twenty-one".