393408640 has 32 divisors (see below), whose sum is σ = 940494060. Its totient is φ = 157363200.

The previous prime is 393408563. The next prime is 393408643. The reversal of 393408640 is 46804393.

It can be written as a sum of positive squares in 2 ways, for example, as 383219776 + 10188864 = 19576^2 + 3192^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a self number, because there is not a number n which added to its sum of digits gives 393408640.

It is not an unprimeable number, because it can be changed into a prime (393408643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 306711 + ... + 307990.

Almost surely, 2^393408640 is an apocalyptic number.

It is an amenable number.

393408640 is an abundant number, since it is smaller than the sum of its proper divisors (547085420).

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

393408640 is an equidigital number, since it uses as much as digits as its factorization.

393408640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 614720 (or 614708 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 37.

The square root of 393408640 is about 19834.5315044243. The cubic root of 393408640 is about 732.7367342393.

The spelling of 393408640 in words is "three hundred ninety-three million, four hundred eight thousand, six hundred forty".