81388177188318 has 768 divisors, whose sum is σ = 245618336710656. Its totient is φ = 18797184000000.

The previous prime is 81388177188317. The next prime is 81388177188343.

81388177188318 is a `hidden beast` number, since 8 + 138 + 8 + 177 + 1 + 8 + 8 + 318 = 666.

81388177188318 is nontrivially palindromic in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81388177188317) by changing a digit.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 31411877203 + ... + 31411879793.

It is an arithmetic number, because the mean of its divisors is an integer number (319815542592).

Almost surely, 2^{81388177188318} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81388177188318, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122809168355328).

81388177188318 is an abundant number, since it is smaller than the sum of its proper divisors (164230159522338).

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

81388177188318 is a wasteful number, since it uses less digits than its factorization.

81388177188318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3193 (or 3190 counting only the distinct ones).

The product of its digits is 115605504, while the sum is 72.

The spelling of 81388177188318 in words is "eighty-one trillion, three hundred eighty-eight billion, one hundred seventy-seven million, one hundred eighty-eight thousand, three hundred eighteen".