391385 has 4 divisors (see below), whose sum is σ = 469668. Its totient is φ = 313104.

The previous prime is 391379. The next prime is 391387. The reversal of 391385 is 583193.

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

It can be written as a sum of positive squares in 2 ways, for example, as 53824 + 337561 = 232^2 + 581^2 .

It is a cyclic number.

It is not a de Polignac number, because 391385 - 2¹⁶ = 325849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391387) 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, 39134 + ... + 39143.

It is an arithmetic number, because the mean of its divisors is an integer number (117417).

391385 is a Friedman number, since it can be written as 31+9^3+5^8, using all its digits and the basic arithmetic operations.

2³⁹¹³⁸⁵ is an apocalyptic number.

It is an amenable number.

391385 is a deficient number, since it is larger than the sum of its proper divisors (78283).

391385 is an equidigital number, since it uses as much as digits as its factorization.

391385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78282.

The product of its digits is 3240, while the sum is 29.

The square root of 391385 is about 625.6077045561. The cubic root of 391385 is about 73.1478208171.

The spelling of 391385 in words is "three hundred ninety-one thousand, three hundred eighty-five".