640447364 has 12 divisors (see below), whose sum is σ = 1179771600. Its totient is φ = 303369768.

The previous prime is 640447361. The next prime is 640447373. The reversal of 640447364 is 463744046.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is not an unprimeable number, because it can be changed into a prime (640447361) 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, 4213394 + ... + 4213545.

It is an arithmetic number, because the mean of its divisors is an integer number (98314300).

Almost surely, 2^640447364 is an apocalyptic number.

It is an amenable number.

640447364 is a deficient number, since it is larger than the sum of its proper divisors (539324236).

640447364 is a wasteful number, since it uses less digits than its factorization.

640447364 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8426962 (or 8426960 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 38.

The square root of 640447364 is about 25307.0615441619. The cubic root of 640447364 is about 861.9746243537.

The spelling of 640447364 in words is "six hundred forty million, four hundred forty-seven thousand, three hundred sixty-four".