638318106864 has 120 divisors (see below), whose sum is σ = 1864749219840. Its totient is φ = 203447984256.

The previous prime is 638318106859. The next prime is 638318106869. The reversal of 638318106864 is 468601813836.

638318106864 is a `hidden beast` number, since 6 + 383 + 181 + 0 + 6 + 86 + 4 = 666.

638318106864 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (638318106859) and next prime (638318106869).

It is a self number, because there is not a number n which added to its sum of digits gives 638318106864.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638318106869) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9501777 + ... + 9568719.

It is an arithmetic number, because the mean of its divisors is an integer number (15539576832).

Almost surely, 2^638318106864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638318106864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (932374609920).

638318106864 is an abundant number, since it is smaller than the sum of its proper divisors (1226431112976).

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

638318106864 is a wasteful number, since it uses less digits than its factorization.

638318106864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69859 (or 69850 counting only the distinct ones).

The product of its (nonzero) digits is 3981312, while the sum is 54.

The spelling of 638318106864 in words is "six hundred thirty-eight billion, three hundred eighteen million, one hundred six thousand, eight hundred sixty-four".