18799728138 has 24 divisors (see below), whose sum is σ = 40826832228. Its totient is φ = 6252100992.

The previous prime is 18799728053. The next prime is 18799728139. The reversal of 18799728138 is 83182799781.

It can be written as a sum of positive squares in 2 ways, for example, as 16881025329 + 1918702809 = 129927^2 + 43803^2 .

It is not an unprimeable number, because it can be changed into a prime (18799728139) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1198245 + ... + 1213832.

Almost surely, 2^18799728138 is an apocalyptic number.

18799728138 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

18799728138 is an abundant number, since it is smaller than the sum of its proper divisors (22027104090).

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

18799728138 is a wasteful number, since it uses less digits than its factorization.

18799728138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2412518 (or 2412515 counting only the distinct ones).

The product of its digits is 12192768, while the sum is 63.

The spelling of 18799728138 in words is "eighteen billion, seven hundred ninety-nine million, seven hundred twenty-eight thousand, one hundred thirty-eight".