81808619689 has 8 divisors (see below), whose sum is σ = 81886531680. Its totient is φ = 81730742496.

The previous prime is 81808619681. The next prime is 81808619741. The reversal of 81808619689 is 98691680818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81808619689 - 2³ = 81808619681 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81808619689.

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 7 ways as a sum of consecutive naturals, for example, 7440454 + ... + 7451440.

It is an arithmetic number, because the mean of its divisors is an integer number (10235816460).

Almost surely, 2^81808619689 is an apocalyptic number.

It is an amenable number.

81808619689 is a deficient number, since it is larger than the sum of its proper divisors (77911991).

81808619689 is a wasteful number, since it uses less digits than its factorization.

81808619689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17399.

The product of its (nonzero) digits is 11943936, while the sum is 64.

The spelling of 81808619689 in words is "eighty-one billion, eight hundred eight million, six hundred nineteen thousand, six hundred eighty-nine".