390639605 has 6 divisors (see below), whose sum is σ = 468820566. Its totient is φ = 312476328.

The previous prime is 390639593. The next prime is 390639629. The reversal of 390639605 is 506936093.

It can be written as a sum of positive squares in only one way, i.e., 312511684 + 78127921 = 17678^2 + 8839^2 .

It is not a de Polignac number, because 390639605 - 2⁴ = 390639589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 39776 + ... + 48614.

It is an arithmetic number, because the mean of its divisors is an integer number (78136761).

Almost surely, 2^390639605 is an apocalyptic number.

It is an amenable number.

390639605 is a deficient number, since it is larger than the sum of its proper divisors (78180961).

390639605 is an frugal number, since it uses more digits than its factorization.

390639605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17683 (or 8844 counting only the distinct ones).

The product of its (nonzero) digits is 131220, while the sum is 41.

The square root of 390639605 is about 19764.6048531206. The cubic root of 390639605 is about 731.0135448992.

Multiplying 390639605 by its product of nonzero digits (131220), we get a square (51259728968100 = 7159590²).

The spelling of 390639605 in words is "three hundred ninety million, six hundred thirty-nine thousand, six hundred five".