390999 has 16 divisors (see below), whose sum is σ = 611072. Its totient is φ = 217728.

The previous prime is 390991. The next prime is 391009. The reversal of 390999 is 999093.

390999 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 390999 - 2³ = 390991 is a prime.

390999 is a modest number, since divided by 999 gives 390 as remainder.

390999 is strictly pandigital in base 7.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (390991) 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, 687 + ... + 1119.

It is an arithmetic number, because the mean of its divisors is an integer number (38192).

2³⁹⁰⁹⁹⁹ is an apocalyptic number.

390999 is a deficient number, since it is larger than the sum of its proper divisors (220073).

390999 is a wasteful number, since it uses less digits than its factorization.

390999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 486.

The product of its (nonzero) digits is 19683, while the sum is 39.

The square root of 390999 is about 625.2991284178. The cubic root of 390999 is about 73.1237657765.

The spelling of 390999 in words is "three hundred ninety thousand, nine hundred ninety-nine".