18518891687778 has 64 divisors (see below), whose sum is σ = 37267806015360. Its totient is φ = 6134764339200.

The previous prime is 18518891687771. The next prime is 18518891687783. The reversal of 18518891687778 is 87778619881581.

It is a self number, because there is not a number n which added to its sum of digits gives 18518891687778.

It is not an unprimeable number, because it can be changed into a prime (18518891687771) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1055860533 + ... + 1055878071.

It is an arithmetic number, because the mean of its divisors is an integer number (582309468990).

Almost surely, 2^{18518891687778} is an apocalyptic number.

18518891687778 is an abundant number, since it is smaller than the sum of its proper divisors (18748914327582).

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

18518891687778 is a wasteful number, since it uses less digits than its factorization.

18518891687778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19443.

The product of its digits is 3034644480, while the sum is 84.

The spelling of 18518891687778 in words is "eighteen trillion, five hundred eighteen billion, eight hundred ninety-one million, six hundred eighty-seven thousand, seven hundred seventy-eight".