391439 has 4 divisors (see below), whose sum is σ = 393624. Its totient is φ = 389256.

The previous prime is 391403. The next prime is 391441. The reversal of 391439 is 934193.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 934193 = 13 ⋅71861.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-391439 is a prime.

It is a Duffinian number.

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 391439.

It is not an unprimeable number, because it can be changed into a prime (391639) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 797 + ... + 1190.

It is an arithmetic number, because the mean of its divisors is an integer number (98406).

2³⁹¹⁴³⁹ is an apocalyptic number.

391439 is a deficient number, since it is larger than the sum of its proper divisors (2185).

391439 is a wasteful number, since it uses less digits than its factorization.

391439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2184.

The product of its digits is 2916, while the sum is 29.

The square root of 391439 is about 625.6508611039. The cubic root of 391439 is about 73.1511847687.

The spelling of 391439 in words is "three hundred ninety-one thousand, four hundred thirty-nine".