638045864 has 16 divisors (see below), whose sum is σ = 1196706420. Its totient is φ = 318924160.

The previous prime is 638045843. The next prime is 638045869. The reversal of 638045864 is 468540836.

It can be written as a sum of positive squares in 2 ways, for example, as 625500100 + 12545764 = 25010^2 + 3542^2 .

It is not an unprimeable number, because it can be changed into a prime (638045869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20132 + ... + 41004.

Almost surely, 2^638045864 is an apocalyptic number.

It is an amenable number.

638045864 is a deficient number, since it is larger than the sum of its proper divisors (558660556).

638045864 is a wasteful number, since it uses less digits than its factorization.

638045864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24700 (or 24696 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 44.

The square root of 638045864 is about 25259.5697508885. The cubic root of 638045864 is about 860.8958863085.

The spelling of 638045864 in words is "six hundred thirty-eight million, forty-five thousand, eight hundred sixty-four".