81108992 has 28 divisors (see below), whose sum is σ = 162224466. Its totient is φ = 40550400.

The previous prime is 81108991. The next prime is 81109001. The reversal of 81108992 is 29980118.

It can be written as a sum of positive squares in only one way, i.e., 48664576 + 32444416 = 6976^2 + 5696^2 .

It is not an unprimeable number, because it can be changed into a prime (81108991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3242 + ... + 13142.

Almost surely, 2^81108992 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 81108992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81112233).

81108992 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81108992 is an frugal number, since it uses more digits than its factorization.

81108992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9927 (or 9903 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 81108992 is about 9006.0530755709. The cubic root of 81108992 is about 432.8688503666.

The spelling of 81108992 in words is "eighty-one million, one hundred eight thousand, nine hundred ninety-two".