81018898000 has 80 divisors (see below), whose sum is σ = 196717744080. Its totient is φ = 32272896000.

The previous prime is 81018897989. The next prime is 81018898021. The reversal of 81018898000 is 89881018.

It can be written as a sum of positive squares in 8 ways, for example, as 39074219584 + 41944678416 = 197672^2 + 204804^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 397956 + ... + 566044.

It is an arithmetic number, because the mean of its divisors is an integer number (2458971801).

Almost surely, 2^81018898000 is an apocalyptic number.

81018898000 is a gapful number since it is divisible by the number (80) 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 81018898000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98358872040).

81018898000 is an abundant number, since it is smaller than the sum of its proper divisors (115698846080).

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

81018898000 is a wasteful number, since it uses less digits than its factorization.

81018898000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168353 (or 168337 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 43.

The spelling of 81018898000 in words is "eighty-one billion, eighteen million, eight hundred ninety-eight thousand".