391404 has 36 divisors (see below), whose sum is σ = 994056. Its totient is φ = 119808.

The previous prime is 391403. The next prime is 391441. The reversal of 391404 is 404193.

391404 = T₁₆ + T₁₇ + ... + T₁₃₂.

391404 = 2² + 3² + ... + 105².

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 391404.

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

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1932 + ... + 2124.

2³⁹¹⁴⁰⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 391404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (497028).

391404 is an abundant number, since it is smaller than the sum of its proper divisors (602652).

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

391404 is a wasteful number, since it uses less digits than its factorization.

391404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226 (or 211 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 391404 is about 625.6228896068. The cubic root of 391404 is about 73.1490044650.

Adding to 391404 its reverse (404193), we get a palindrome (795597).

It can be divided in two parts, 39 and 1404, that multiplied together give a square (54756 = 234²).

The spelling of 391404 in words is "three hundred ninety-one thousand, four hundred four".