390406 has 4 divisors (see below), whose sum is σ = 585612. Its totient is φ = 195202.

The previous prime is 390391. The next prime is 390407. The reversal of 390406 is 604093.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a nialpdrome in base 5.

It is a congruent number.

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

390406 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97600 + ... + 97603.

It is an arithmetic number, because the mean of its divisors is an integer number (146403).

2³⁹⁰⁴⁰⁶ is an apocalyptic number.

390406 is a deficient number, since it is larger than the sum of its proper divisors (195206).

390406 is a wasteful number, since it uses less digits than its factorization.

390406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195205.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 390406 is about 624.8247754371. The cubic root of 390406 is about 73.0867798907.

Adding to 390406 its reverse (604093), we get a palindrome (994499).

It can be divided in two parts, 3 and 90406, that added together give a palindrome (90409).

The spelling of 390406 in words is "three hundred ninety thousand, four hundred six".