638798564 has 12 divisors (see below), whose sum is σ = 1121935164. Its totient is φ = 318245664.

The previous prime is 638798561. The next prime is 638798591. The reversal of 638798564 is 465897836.

It can be written as a sum of positive squares in 2 ways, for example, as 245172964 + 393625600 = 15658^2 + 19840^2 .

It is not an unprimeable number, because it can be changed into a prime (638798561) 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, 287159 + ... + 289374.

It is an arithmetic number, because the mean of its divisors is an integer number (93494597).

Almost surely, 2^638798564 is an apocalyptic number.

It is an amenable number.

638798564 is a deficient number, since it is larger than the sum of its proper divisors (483136600).

638798564 is a wasteful number, since it uses less digits than its factorization.

638798564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 576814 (or 576812 counting only the distinct ones).

The product of its digits is 8709120, while the sum is 56.

The square root of 638798564 is about 25274.4646629756. The cubic root of 638798564 is about 861.2342850163.

The spelling of 638798564 in words is "six hundred thirty-eight million, seven hundred ninety-eight thousand, five hundred sixty-four".