81133418368 has 64 divisors (see below), whose sum is σ = 165783309120. Its totient is φ = 39532503040.

The previous prime is 81133418341. The next prime is 81133418393. The reversal of 81133418368 is 86381433118.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1372788 + ... + 1430668.

It is an arithmetic number, because the mean of its divisors is an integer number (2590364205).

Almost surely, 2^81133418368 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81133418368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82891654560).

81133418368 is an abundant number, since it is smaller than the sum of its proper divisors (84649890752).

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

81133418368 is a wasteful number, since it uses less digits than its factorization.

81133418368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58175 (or 58163 counting only the distinct ones).

The product of its digits is 331776, while the sum is 46.

The spelling of 81133418368 in words is "eighty-one billion, one hundred thirty-three million, four hundred eighteen thousand, three hundred sixty-eight".