81081018 has 48 divisors (see below), whose sum is σ = 187324800. Its totient is φ = 25272000.

The previous prime is 81081001. The next prime is 81081019. The reversal of 81081018 is 81018018.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81080982 and 81081000.

It is not an unprimeable number, because it can be changed into a prime (81081019) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25518 + ... + 28518.

It is an arithmetic number, because the mean of its divisors is an integer number (3902600).

Almost surely, 2^81081018 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81081018, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93662400).

81081018 is an abundant number, since it is smaller than the sum of its proper divisors (106243782).

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

81081018 is a wasteful number, since it uses less digits than its factorization.

81081018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3107 (or 3104 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 27.

The square root of 81081018 is about 9004.4998750625. The cubic root of 81081018 is about 432.8190800296.

The spelling of 81081018 in words is "eighty-one million, eighty-one thousand, eighteen".