390649685 has 4 divisors (see below), whose sum is σ = 468779628. Its totient is φ = 312519744.

The previous prime is 390649669. The next prime is 390649717. The reversal of 390649685 is 586946093.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 586946093 = 829 ⋅708017.

It can be written as a sum of positive squares in 2 ways, for example, as 168013444 + 222636241 = 12962^2 + 14921^2 .

It is a cyclic number.

It is not a de Polignac number, because 390649685 - 2⁴ = 390649669 is a prime.

It is a Duffinian number.

It is a Curzon 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, 39064964 + ... + 39064973.

It is an arithmetic number, because the mean of its divisors is an integer number (117194907).

Almost surely, 2^390649685 is an apocalyptic number.

It is an amenable number.

390649685 is a deficient number, since it is larger than the sum of its proper divisors (78129943).

390649685 is an equidigital number, since it uses as much as digits as its factorization.

390649685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78129942.

The product of its (nonzero) digits is 1399680, while the sum is 50.

The square root of 390649685 is about 19764.8598527791. The cubic root of 390649685 is about 731.0198324961.

The spelling of 390649685 in words is "three hundred ninety million, six hundred forty-nine thousand, six hundred eighty-five".