405984 has 24 divisors (see below), whose sum is σ = 1065960. Its totient is φ = 135296.

The previous prime is 405967. The next prime is 405989. The reversal of 405984 is 489504.

It is a tau number, because it is divible by the number of its divisors (24).

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors.

It is an Ulam number.

It is a zygodrome in base 2.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 405984.

It is not an unprimeable number, because it can be changed into a prime (405989) by changing a digit.

405984 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 in 3 ways as a sum of consecutive naturals, for example, 2019 + ... + 2210.

It is an arithmetic number, because the mean of its divisors is an integer number (44415).

2⁴⁰⁵⁹⁸⁴ is an apocalyptic number.

It is an amenable number.

405984 is an abundant number, since it is smaller than the sum of its proper divisors (659976).

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

405984 is a wasteful number, since it uses less digits than its factorization.

405984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4242 (or 4234 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 405984 is about 637.1687374628. The cubic root of 405984 is about 74.0462335869.

The spelling of 405984 in words is "four hundred five thousand, nine hundred eighty-four".