390865 has 4 divisors (see below), whose sum is σ = 469044. Its totient is φ = 312688.

The previous prime is 390851. The next prime is 390869. The reversal of 390865 is 568093.

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 266256 + 124609 = 516^2 + 353^2 .

It is a cyclic number.

It is not a de Polignac number, because 390865 - 2⁷ = 390737 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a d-powerful number, because it can be written as 3³ + 9 + 8⁵ + 0 + 6⁷ + 5⁷ .

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (390869) 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, 39082 + ... + 39091.

It is an arithmetic number, because the mean of its divisors is an integer number (117261).

2³⁹⁰⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

390865 is a deficient number, since it is larger than the sum of its proper divisors (78179).

390865 is an equidigital number, since it uses as much as digits as its factorization.

390865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78178.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 390865 is about 625.1919705179. The cubic root of 390865 is about 73.1154113611.

The spelling of 390865 in words is "three hundred ninety thousand, eight hundred sixty-five".