390685 has 4 divisors (see below), whose sum is σ = 468828. Its totient is φ = 312544.

The previous prime is 390673. The next prime is 390703. The reversal of 390685 is 586093.

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 213444 + 177241 = 462^2 + 421^2 .

It is a cyclic number.

It is not a de Polignac number, because 390685 - 2⁵ = 390653 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 Duffinian number.

390685 is a lucky number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39064 + ... + 39073.

It is an arithmetic number, because the mean of its divisors is an integer number (117207).

390685 is a Friedman number, since it can be written as 5^8+6*(9+3^0), using all its digits and the basic arithmetic operations.

2³⁹⁰⁶⁸⁵ is an apocalyptic number.

It is an amenable number.

390685 is a deficient number, since it is larger than the sum of its proper divisors (78143).

390685 is an equidigital number, since it uses as much as digits as its factorization.

390685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78142.

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

The square root of 390685 is about 625.0479981569. The cubic root of 390685 is about 73.1041860064.

The spelling of 390685 in words is "three hundred ninety thousand, six hundred eighty-five".