390840 has 32 divisors (see below), whose sum is σ = 1172880. Its totient is φ = 104192.

The previous prime is 390829. The next prime is 390851. The reversal of 390840 is 48093.

390840 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (390829) and next prime (390851).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 390840.

It is a congruent 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, 1509 + ... + 1748.

2³⁹⁰⁸⁴⁰ is an apocalyptic number.

390840 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

390840 is an abundant number, since it is smaller than the sum of its proper divisors (782040).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

390840 is a wasteful number, since it uses less digits than its factorization.

390840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3271 (or 3267 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 390840 is about 625.1719763393. The cubic root of 390840 is about 73.1138524902.

The spelling of 390840 in words is "three hundred ninety thousand, eight hundred forty".