81989792 has 24 divisors (see below), whose sum is σ = 166626432. Its totient is φ = 39672000.

The previous prime is 81989771. The next prime is 81989801. The reversal of 81989792 is 29798918.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40334 + ... + 42317.

It is an arithmetic number, because the mean of its divisors is an integer number (6942768).

Almost surely, 2^81989792 is an apocalyptic number.

It is an amenable number.

81989792 is an abundant number, since it is smaller than the sum of its proper divisors (84636640).

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

81989792 is a wasteful number, since it uses less digits than its factorization.

81989792 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82692 (or 82684 counting only the distinct ones).

The product of its digits is 653184, while the sum is 53.

The square root of 81989792 is about 9054.8214780856. The cubic root of 81989792 is about 434.4301199966.

The spelling of 81989792 in words is "eighty-one million, nine hundred eighty-nine thousand, seven hundred ninety-two".