18891931968 has 504 divisors, whose sum is σ = 70386013152. Its totient is φ = 4979874816.

The previous prime is 18891931957. The next prime is 18891932063. The reversal of 18891931968 is 86913919881.

It is a tau number, because it is divible by the number of its divisors (504).

It is a super-3 number, since 3×18891931968³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 9905671 + ... + 9907577.

It is an arithmetic number, because the mean of its divisors is an integer number (139654788).

Almost surely, 2^18891931968 is an apocalyptic number.

18891931968 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 18891931968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35193006576).

18891931968 is an abundant number, since it is smaller than the sum of its proper divisors (51494081184).

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

18891931968 is a wasteful number, since it uses less digits than its factorization.

18891931968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1961 (or 1932 counting only the distinct ones).

The product of its digits is 6718464, while the sum is 63.

The spelling of 18891931968 in words is "eighteen billion, eight hundred ninety-one million, nine hundred thirty-one thousand, nine hundred sixty-eight".