81931945068 has 96 divisors (see below), whose sum is σ = 216591883200. Its totient is φ = 26774572032.

The previous prime is 81931945061. The next prime is 81931945079. The reversal of 81931945068 is 86054913918.

81931945068 is a `hidden beast` number, since 8 + 19 + 31 + 94 + 506 + 8 = 666.

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

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

It is not an unprimeable number, because it can be changed into a prime (81931945061) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8518230 + ... + 8527842.

It is an arithmetic number, because the mean of its divisors is an integer number (2256165450).

Almost surely, 2^81931945068 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 81931945068, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108295941600).

81931945068 is an abundant number, since it is smaller than the sum of its proper divisors (134659938132).

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

81931945068 is a wasteful number, since it uses less digits than its factorization.

81931945068 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11168 (or 11160 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 54.

The spelling of 81931945068 in words is "eighty-one billion, nine hundred thirty-one million, nine hundred forty-five thousand, sixty-eight".