81541086916 has 27 divisors (see below), whose sum is σ = 144926503407. Its totient is φ = 40143181320.

The previous prime is 81541086911. The next prime is 81541086929. The reversal of 81541086916 is 61968014518.

The square root of 81541086916 is 285554.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81541086916.

It is not an unprimeable number, because it can be changed into a prime (81541086911) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 38263171 + ... + 38265301.

Almost surely, 2^81541086916 is an apocalyptic number.

81541086916 is the 285554-th square number.

It is an amenable number.

81541086916 is a deficient number, since it is larger than the sum of its proper divisors (63385416491).

81541086916 is an frugal number, since it uses more digits than its factorization.

81541086916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4400 (or 2200 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 49.

Multiplying 81541086916 by its sum of digits (49), we get a square (3995513258884 = 1998878²).

The spelling of 81541086916 in words is "eighty-one billion, five hundred forty-one million, eighty-six thousand, nine hundred sixteen".