81808619688 has 48 divisors (see below), whose sum is σ = 221923072800. Its totient is φ = 27225470880.

The previous prime is 81808619681. The next prime is 81808619741. The reversal of 81808619688 is 88691680818.

81808619688 is a `hidden beast` number, since 8 + 1 + 8 + 0 + 8 + 619 + 6 + 8 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (81808619681) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 873228 + ... + 962363.

It is an arithmetic number, because the mean of its divisors is an integer number (4623397350).

Almost surely, 2^81808619688 is an apocalyptic number.

It is an amenable number.

81808619688 is an abundant number, since it is smaller than the sum of its proper divisors (140114453112).

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

81808619688 is a wasteful number, since it uses less digits than its factorization.

81808619688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1836222 (or 1836215 counting only the distinct ones).

The product of its (nonzero) digits is 10616832, while the sum is 63.

The spelling of 81808619688 in words is "eighty-one billion, eight hundred eight million, six hundred nineteen thousand, six hundred eighty-eight".