391928 has 8 divisors (see below), whose sum is σ = 734880. Its totient is φ = 195960.

The previous prime is 391921. The next prime is 391939. The reversal of 391928 is 829193.

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 391894 and 391903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391921) 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 as a sum of consecutive naturals, namely, 24488 + ... + 24503.

It is an arithmetic number, because the mean of its divisors is an integer number (91860).

2³⁹¹⁹²⁸ is an apocalyptic number.

It is an amenable number.

391928 is a deficient number, since it is larger than the sum of its proper divisors (342952).

391928 is a wasteful number, since it uses less digits than its factorization.

391928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48997 (or 48993 counting only the distinct ones).

The product of its digits is 3888, while the sum is 32.

The square root of 391928 is about 626.0415321686. The cubic root of 391928 is about 73.1816331436.

The spelling of 391928 in words is "three hundred ninety-one thousand, nine hundred twenty-eight".