18081891784 has 32 divisors (see below), whose sum is σ = 38593765440. Its totient is φ = 7861691200.

The previous prime is 18081891769. The next prime is 18081891799. The reversal of 18081891784 is 48719818081.

It is an interprime number because it is at equal distance from previous prime (18081891769) and next prime (18081891799).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4464847 + ... + 4468894.

It is an arithmetic number, because the mean of its divisors is an integer number (1206055170).

Almost surely, 2^18081891784 is an apocalyptic number.

It is an amenable number.

18081891784 is an abundant number, since it is smaller than the sum of its proper divisors (20511873656).

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

18081891784 is a wasteful number, since it uses less digits than its factorization.

18081891784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8933781 (or 8933777 counting only the distinct ones).

The product of its (nonzero) digits is 1032192, while the sum is 55.

The spelling of 18081891784 in words is "eighteen billion, eighty-one million, eight hundred ninety-one thousand, seven hundred eighty-four".