81517916661066 has 64 divisors (see below), whose sum is σ = 193186768521600. Its totient is φ = 25390260926208.

The previous prime is 81517916661037. The next prime is 81517916661079. The reversal of 81517916661066 is 66016661971518.

It is a junction number, because it is equal to n+sod(n) for n = 81517916660994 and 81517916661012.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 319294965 + ... + 319550168.

It is an arithmetic number, because the mean of its divisors is an integer number (3018543258150).

Almost surely, 2^{81517916661066} is an apocalyptic number.

81517916661066 is an abundant number, since it is smaller than the sum of its proper divisors (111668851860534).

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

81517916661066 is a wasteful number, since it uses less digits than its factorization.

81517916661066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638845300 (or 638845294 counting only the distinct ones).

The product of its (nonzero) digits is 19595520, while the sum is 63.

The spelling of 81517916661066 in words is "eighty-one trillion, five hundred seventeen billion, nine hundred sixteen million, six hundred sixty-one thousand, sixty-six".