18989909568 has 672 divisors, whose sum is σ = 70722183168. Its totient is φ = 4926873600.

The previous prime is 18989909539. The next prime is 18989909611. The reversal of 18989909568 is 86590998981.

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 18989909496 and 18989909505.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 57371163 + ... + 57371493.

It is an arithmetic number, because the mean of its divisors is an integer number (105241344).

Almost surely, 2^18989909568 is an apocalyptic number.

18989909568 is a gapful number since it is divisible by the number (18) 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 18989909568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35361091584).

18989909568 is an abundant number, since it is smaller than the sum of its proper divisors (51732273600).

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

18989909568 is a wasteful number, since it uses less digits than its factorization.

18989909568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 413 (or 391 counting only the distinct ones).

The product of its (nonzero) digits is 100776960, while the sum is 72.

The spelling of 18989909568 in words is "eighteen billion, nine hundred eighty-nine million, nine hundred nine thousand, five hundred sixty-eight".