81696933864 has 384 divisors, whose sum is σ = 291849143040. Its totient is φ = 20032413696.

The previous prime is 81696933859. The next prime is 81696933889. The reversal of 81696933864 is 46833969618.

81696933864 is a `hidden beast` number, since 8 + 169 + 6 + 93 + 386 + 4 = 666.

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 an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 9240454 + ... + 9249290.

It is an arithmetic number, because the mean of its divisors is an integer number (760023810).

Almost surely, 2^81696933864 is an apocalyptic number.

81696933864 is a gapful number since it is divisible by the number (84) 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 81696933864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145924571520).

81696933864 is an abundant number, since it is smaller than the sum of its proper divisors (210152209176).

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

81696933864 is a wasteful number, since it uses less digits than its factorization.

81696933864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8969 (or 8962 counting only the distinct ones).

The product of its digits is 40310784, while the sum is 63.

The spelling of 81696933864 in words is "eighty-one billion, six hundred ninety-six million, nine hundred thirty-three thousand, eight hundred sixty-four".