81347705768 has 32 divisors (see below), whose sum is σ = 174339475200. Its totient is φ = 34858709952.

The previous prime is 81347705723. The next prime is 81347705783. The reversal of 81347705768 is 86750774318.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (56).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 351746 + ... + 535182.

It is an arithmetic number, because the mean of its divisors is an integer number (5448108600).

Almost surely, 2^81347705768 is an apocalyptic number.

It is an amenable number.

81347705768 is an abundant number, since it is smaller than the sum of its proper divisors (92991769432).

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

81347705768 is a wasteful number, since it uses less digits than its factorization.

81347705768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191369 (or 191365 counting only the distinct ones).

The product of its (nonzero) digits is 7902720, while the sum is 56.

The spelling of 81347705768 in words is "eighty-one billion, three hundred forty-seven million, seven hundred five thousand, seven hundred sixty-eight".