18431981568 has 1152 divisors, whose sum is σ = 76126901760. Its totient is φ = 4299816960.

The previous prime is 18431981543. The next prime is 18431981597. The reversal of 18431981568 is 86518913481.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (1152).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 498161646 + ... + 498161682.

It is an arithmetic number, because the mean of its divisors is an integer number (66082380).

Almost surely, 2^18431981568 is an apocalyptic number.

18431981568 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 18431981568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38063450880).

18431981568 is an abundant number, since it is smaller than the sum of its proper divisors (57694920192).

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

18431981568 is a wasteful number, since it uses less digits than its factorization.

18431981568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105 (or 73 counting only the distinct ones).

The product of its digits is 1658880, while the sum is 54.

It can be divided in two parts, 18431 and 981568, that added together give a palindrome (999999).

The spelling of 18431981568 in words is "eighteen billion, four hundred thirty-one million, nine hundred eighty-one thousand, five hundred sixty-eight".