408391 has 4 divisors (see below), whose sum is σ = 432432. Its totient is φ = 384352.

The previous prime is 408389. The next prime is 408403. The reversal of 408391 is 193804.

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

It is a cyclic number.

It is not a de Polignac number, because 408391 - 2¹ = 408389 is a prime.

It is a Duffinian number.

408391 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (408311) 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, 11995 + ... + 12028.

It is an arithmetic number, because the mean of its divisors is an integer number (108108).

2⁴⁰⁸³⁹¹ is an apocalyptic number.

408391 is a deficient number, since it is larger than the sum of its proper divisors (24041).

408391 is a wasteful number, since it uses less digits than its factorization.

408391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24040.

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

The square root of 408391 is about 639.0547707357. The cubic root of 408391 is about 74.1922805666.

The spelling of 408391 in words is "four hundred eight thousand, three hundred ninety-one".