18666385920 has 960 divisors, whose sum is σ = 82577214720. Its totient is φ = 3790209024.

The previous prime is 18666385901. The next prime is 18666385921. The reversal of 18666385920 is 2958366681.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (960).

It is not an unprimeable number, because it can be changed into a prime (18666385921) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 60802407 + ... + 60802713.

It is an arithmetic number, because the mean of its divisors is an integer number (86017932).

Almost surely, 2^18666385920 is an apocalyptic number.

18666385920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18666385920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41288607360).

18666385920 is an abundant number, since it is smaller than the sum of its proper divisors (63910828800).

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

18666385920 is a wasteful number, since it uses less digits than its factorization.

18666385920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385 (or 366 counting only the distinct ones).

The product of its (nonzero) digits is 3732480, while the sum is 54.

The spelling of 18666385920 in words is "eighteen billion, six hundred sixty-six million, three hundred eighty-five thousand, nine hundred twenty".