8728639938 has 90 divisors (see below), whose sum is σ = 20295337257. Its totient is φ = 2711225520.

The previous prime is 8728639901. The next prime is 8728639939. The reversal of 8728639938 is 8399368278.

It can be written as a sum of positive squares in 2 ways, for example, as 5912533449 + 2816106489 = 76893^2 + 53067^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=66063.

It is not an unprimeable number, because it can be changed into a prime (8728639939) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 143092428 + ... + 143092488.

Almost surely, 2^8728639938 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 8728639938

8728639938 is an abundant number, since it is smaller than the sum of its proper divisors (11566697319).

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

8728639938 is an frugal number, since it uses more digits than its factorization.

8728639938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206 (or 85 counting only the distinct ones).

The product of its digits is 31352832, while the sum is 63.

The square root of 8728639938 is about 93427.1905710538. The cubic root of 8728639938 is about 2058.9645043986.

The spelling of 8728639938 in words is "eight billion, seven hundred twenty-eight million, six hundred thirty-nine thousand, nine hundred thirty-eight".