391885 has 8 divisors (see below), whose sum is σ = 506520. Its totient is φ = 289344.

The previous prime is 391879. The next prime is 391889. The reversal of 391885 is 588193.

It can be written as a sum of positive squares in 4 ways, for example, as 56644 + 335241 = 238^2 + 579^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 391885 - 2⁷ = 391757 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 391885.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391889) 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, 2950 + ... + 3079.

It is an arithmetic number, because the mean of its divisors is an integer number (63315).

2³⁹¹⁸⁸⁵ is an apocalyptic number.

It is an amenable number.

391885 is a deficient number, since it is larger than the sum of its proper divisors (114635).

391885 is a wasteful number, since it uses less digits than its factorization.

391885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6047.

The product of its digits is 8640, while the sum is 34.

The square root of 391885 is about 626.0071884571. The cubic root of 391885 is about 73.1789566951.

It can be divided in two parts, 39188 and 5, that added together give a palindrome (39193).

The spelling of 391885 in words is "three hundred ninety-one thousand, eight hundred eighty-five".