81648084688 has 10 divisors (see below), whose sum is σ = 158193164114. Its totient is φ = 40824042336.

The previous prime is 81648084613. The next prime is 81648084689. The reversal of 81648084688 is 88648084618.

It can be written as a sum of positive squares in only one way, i.e., 81024483904 + 623600784 = 284648^2 + 24972^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81648084689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2551502631 + ... + 2551502662.

Almost surely, 2^81648084688 is an apocalyptic number.

It is an amenable number.

81648084688 is a deficient number, since it is larger than the sum of its proper divisors (76545079426).

81648084688 is a wasteful number, since it uses less digits than its factorization.

81648084688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5103005301 (or 5103005295 counting only the distinct ones).

The product of its (nonzero) digits is 18874368, while the sum is 61.

The spelling of 81648084688 in words is "eighty-one billion, six hundred forty-eight million, eighty-four thousand, six hundred eighty-eight".