81318992832 has 504 divisors, whose sum is σ = 305575216128. Its totient is φ = 20200688640.

The previous prime is 81318992819. The next prime is 81318992863. The reversal of 81318992832 is 23829981318.

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

It is a super-2 number, since 2×81318992832² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

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, 11217433 + ... + 11224679.

It is an arithmetic number, because the mean of its divisors is an integer number (606300032).

Almost surely, 2^81318992832 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 81318992832, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (152787608064).

81318992832 is an abundant number, since it is smaller than the sum of its proper divisors (224256223296).

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

81318992832 is a wasteful number, since it uses less digits than its factorization.

81318992832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7317 (or 7293 counting only the distinct ones).

The product of its digits is 1492992, while the sum is 54.

The spelling of 81318992832 in words is "eighty-one billion, three hundred eighteen million, nine hundred ninety-two thousand, eight hundred thirty-two".