405640320 has 64 divisors (see below), whose sum is σ = 1292984640. Its totient is φ = 108170240.

The previous prime is 405640307. The next prime is 405640337. The reversal of 405640320 is 23046504.

It is a tau number, because it is divible by the number of its divisors (64).

It is a hoax number, since the sum of its digits (24) coincides with the sum of the digits of its distinct prime factors.

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

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, 103716 + ... + 107555.

It is an arithmetic number, because the mean of its divisors is an integer number (20202885).

Almost surely, 2^405640320 is an apocalyptic number.

405640320 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

405640320 is an abundant number, since it is smaller than the sum of its proper divisors (887344320).

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

405640320 is a wasteful number, since it uses less digits than its factorization.

405640320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211293 (or 211281 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 24.

The square root of 405640320 is about 20140.5143926365. The cubic root of 405640320 is about 740.2533342513.

Adding to 405640320 its reverse (23046504), we get a palindrome (428686824).

The spelling of 405640320 in words is "four hundred five million, six hundred forty thousand, three hundred twenty".