390905 has 8 divisors (see below), whose sum is σ = 481992. Its totient is φ = 304128.

The previous prime is 390893. The next prime is 390953. The reversal of 390905 is 509093.

It can be written as a sum of positive squares in 4 ways, for example, as 11449 + 379456 = 107^2 + 616^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 390905 - 2⁴ = 390889 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 872 + ... + 1241.

It is an arithmetic number, because the mean of its divisors is an integer number (60249).

2³⁹⁰⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

390905 is a deficient number, since it is larger than the sum of its proper divisors (91087).

390905 is a wasteful number, since it uses less digits than its factorization.

390905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2155.

The product of its (nonzero) digits is 1215, while the sum is 26.

The square root of 390905 is about 625.2239598736. The cubic root of 390905 is about 73.1179054164.

Adding to 390905 its reverse (509093), we get a palindrome (899998).

The spelling of 390905 in words is "three hundred ninety thousand, nine hundred five".