390405 has 16 divisors (see below), whose sum is σ = 661824. Its totient is φ = 195840.

The previous prime is 390391. The next prime is 390407. The reversal of 390405 is 504093.

It is not a de Polignac number, because 390405 - 2⁴ = 390389 is a prime.

It is an Ulam number.

390405 is a modest number, since divided by 405 gives 390 as remainder.

It is a nialpdrome in base 5.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (390407) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 511 + ... + 1020.

It is an arithmetic number, because the mean of its divisors is an integer number (41364).

2³⁹⁰⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

390405 is a deficient number, since it is larger than the sum of its proper divisors (271419).

390405 is a wasteful number, since it uses less digits than its factorization.

390405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1556.

The product of its (nonzero) digits is 540, while the sum is 21.

The square root of 390405 is about 624.8239752122. The cubic root of 390405 is about 73.0867174883.

Adding to 390405 its reverse (504093), we get a palindrome (894498).

The spelling of 390405 in words is "three hundred ninety thousand, four hundred five".