18398308640 has 24 divisors (see below), whose sum is σ = 43466004540. Its totient is φ = 7359323392.

The previous prime is 18398308639. The next prime is 18398308651. The reversal of 18398308640 is 4680389381.

It can be written as a sum of positive squares in 2 ways, for example, as 17679425296 + 718883344 = 132964^2 + 26812^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57494555 + ... + 57494874.

Almost surely, 2^18398308640 is an apocalyptic number.

18398308640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18398308640 is an abundant number, since it is smaller than the sum of its proper divisors (25067695900).

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

18398308640 is a wasteful number, since it uses less digits than its factorization.

18398308640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114989444 (or 114989436 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 50.

The spelling of 18398308640 in words is "eighteen billion, three hundred ninety-eight million, three hundred eight thousand, six hundred forty".