18999981036 has 36 divisors (see below), whose sum is σ = 50115894192. Its totient is φ = 6057964704.

The previous prime is 18999981017. The next prime is 18999981047. The reversal of 18999981036 is 63018999981.

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11472591 + ... + 11474246.

It is an arithmetic number, because the mean of its divisors is an integer number (1392108172).

Almost surely, 2^18999981036 is an apocalyptic number.

It is an amenable number.

18999981036 is an abundant number, since it is smaller than the sum of its proper divisors (31115913156).

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

18999981036 is a wasteful number, since it uses less digits than its factorization.

18999981036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22946870 (or 22946865 counting only the distinct ones).

The product of its (nonzero) digits is 7558272, while the sum is 63.

The spelling of 18999981036 in words is "eighteen billion, nine hundred ninety-nine million, nine hundred eighty-one thousand, thirty-six".