81647606688 has 48 divisors (see below), whose sum is σ = 216534528000. Its totient is φ = 26935289856.

The previous prime is 81647606669. The next prime is 81647606737. The reversal of 81647606688 is 88660674618.

It is a tau number, because it is divible by the number of its divisors (48).

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, 4374688 + ... + 4393311.

It is an arithmetic number, because the mean of its divisors is an integer number (4511136000).

Almost surely, 2^81647606688 is an apocalyptic number.

It is an amenable number.

81647606688 is an abundant number, since it is smaller than the sum of its proper divisors (134886921312).

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

81647606688 is a wasteful number, since it uses less digits than its factorization.

81647606688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8768109 (or 8768101 counting only the distinct ones).

The product of its (nonzero) digits is 18579456, while the sum is 60.

The spelling of 81647606688 in words is "eighty-one billion, six hundred forty-seven million, six hundred six thousand, six hundred eighty-eight".