405444 has 48 divisors (see below), whose sum is σ = 1072512. Its totient is φ = 118272.

The previous prime is 405439. The next prime is 405473. The reversal of 405444 is 444504.

It is a Smith number, since the sum of its digits (21) coincides with the sum of the digits of its prime factors.

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 405444.

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 405444.

It is an unprimeable number.

405444 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 15 ways as a sum of consecutive naturals, for example, 3532 + ... + 3644.

It is an arithmetic number, because the mean of its divisors is an integer number (22344).

2⁴⁰⁵⁴⁴⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 405444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (536256).

405444 is an abundant number, since it is smaller than the sum of its proper divisors (667068).

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

405444 is a wasteful number, since it uses less digits than its factorization.

405444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 21.

The square root of 405444 is about 636.7448468578. The cubic root of 405444 is about 74.0133893474.

Adding to 405444 its reverse (444504), we get a palindrome (849948).

Subtracting 405444 from its reverse (444504), we obtain a triangular number (39060 = T₂₇₉).

The spelling of 405444 in words is "four hundred five thousand, four hundred forty-four".