18019981981836 has 72 divisors (see below), whose sum is σ = 50016246330960. Its totient is φ = 5653327675392.

The previous prime is 18019981981789. The next prime is 18019981981849. The reversal of 18019981981836 is 63818918991081.

18019981981836 is a `hidden beast` number, since 180 + 199 + 81 + 9 + 8 + 183 + 6 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 545250421 + ... + 545283468.

It is an arithmetic number, because the mean of its divisors is an integer number (694670087930).

Almost surely, 2^{18019981981836} is an apocalyptic number.

It is an amenable number.

18019981981836 is an abundant number, since it is smaller than the sum of its proper divisors (31996264349124).

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

18019981981836 is a wasteful number, since it uses less digits than its factorization.

18019981981836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1090533925 (or 1090533911 counting only the distinct ones).

The product of its (nonzero) digits is 53747712, while the sum is 72.

The spelling of 18019981981836 in words is "eighteen trillion, nineteen billion, nine hundred eighty-one million, nine hundred eighty-one thousand, eight hundred thirty-six".