638515548636 has 144 divisors (see below), whose sum is σ = 1740307038624. Its totient is φ = 181677371904.

The previous prime is 638515548589. The next prime is 638515548673. The reversal of 638515548636 is 636845515836.

638515548636 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 638515548636.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 187081666 + ... + 187085078.

It is an arithmetic number, because the mean of its divisors is an integer number (12085465546).

Almost surely, 2^638515548636 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 638515548636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (870153519312).

638515548636 is an abundant number, since it is smaller than the sum of its proper divisors (1101791489988).

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

638515548636 is a wasteful number, since it uses less digits than its factorization.

638515548636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4660 (or 4651 counting only the distinct ones).

The product of its digits is 62208000, while the sum is 60.

The spelling of 638515548636 in words is "six hundred thirty-eight billion, five hundred fifteen million, five hundred forty-eight thousand, six hundred thirty-six".