391406 has 16 divisors (see below), whose sum is σ = 622080. Its totient is φ = 184440.

The previous prime is 391403. The next prime is 391441. The reversal of 391406 is 604193.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 391406.

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 (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3605 + ... + 3711.

It is an arithmetic number, because the mean of its divisors is an integer number (38880).

2³⁹¹⁴⁰⁶ is an apocalyptic number.

391406 is a deficient number, since it is larger than the sum of its proper divisors (230674).

391406 is a wasteful number, since it uses less digits than its factorization.

391406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 391406 is about 625.6244880118. The cubic root of 391406 is about 73.1491290573.

Adding to 391406 its reverse (604193), we get a palindrome (995599).

It can be divided in two parts, 391 and 406, that added together give a palindrome (797).

The spelling of 391406 in words is "three hundred ninety-one thousand, four hundred six".