391408 has 20 divisors (see below), whose sum is σ = 803520. Its totient is φ = 184064.

The previous prime is 391403. The next prime is 391441. The reversal of 391408 is 804193.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 448 + ... + 991.

It is an arithmetic number, because the mean of its divisors is an integer number (40176).

2³⁹¹⁴⁰⁸ is an apocalyptic number.

It is an amenable number.

391408 is an abundant number, since it is smaller than the sum of its proper divisors (412112).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

391408 is a wasteful number, since it uses less digits than its factorization.

391408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1464 (or 1458 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 391408 is about 625.6260864126. The cubic root of 391408 is about 73.1492536491.

The spelling of 391408 in words is "three hundred ninety-one thousand, four hundred eight".