81818865900 has 432 divisors, whose sum is σ = 280558605600. Its totient is φ = 19871723520.

The previous prime is 81818865899. The next prime is 81818865983. The reversal of 81818865900 is 956881818.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 56309574 + ... + 56311026.

Almost surely, 2^81818865900 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 81818865900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140279302800).

81818865900 is an abundant number, since it is smaller than the sum of its proper divisors (198739739700).

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

81818865900 is a wasteful number, since it uses less digits than its factorization.

81818865900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1618 (or 1608 counting only the distinct ones).

The product of its (nonzero) digits is 1105920, while the sum is 54.

The spelling of 81818865900 in words is "eighty-one billion, eight hundred eighteen million, eight hundred sixty-five thousand, nine hundred".