81680520344 has 64 divisors (see below), whose sum is σ = 156227097600. Its totient is φ = 40027680000.

The previous prime is 81680520217. The next prime is 81680520359. The reversal of 81680520344 is 44302508618.

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, 108761969 + ... + 108762719.

It is an arithmetic number, because the mean of its divisors is an integer number (2441048400).

Almost surely, 2^81680520344 is an apocalyptic number.

It is an amenable number.

81680520344 is a deficient number, since it is larger than the sum of its proper divisors (74546577256).

81680520344 is a wasteful number, since it uses less digits than its factorization.

81680520344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1704 (or 1700 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 41.

The spelling of 81680520344 in words is "eighty-one billion, six hundred eighty million, five hundred twenty thousand, three hundred forty-four".