405640256 has 56 divisors (see below), whose sum is σ = 931103040. Its totient is φ = 171735552.

The previous prime is 405640231. The next prime is 405640297. The reversal of 405640256 is 652046504.

It is a tau number, because it is divible by the number of its divisors (56).

It is a Harshad number since it is a multiple of its sum of digits (32).

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, 31730 + ... + 42638.

It is an arithmetic number, because the mean of its divisors is an integer number (16626840).

Almost surely, 2^405640256 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 405640256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (465551520).

405640256 is an abundant number, since it is smaller than the sum of its proper divisors (525462784).

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

405640256 is a wasteful number, since it uses less digits than its factorization.

405640256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11011 (or 11001 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 32.

The square root of 405640256 is about 20140.5128037992. The cubic root of 405640256 is about 740.2532953201.

The spelling of 405640256 in words is "four hundred five million, six hundred forty thousand, two hundred fifty-six".