81679690697 has 16 divisors (see below), whose sum is σ = 90208823040. Its totient is φ = 73335109200.

The previous prime is 81679690681. The next prime is 81679690721. The reversal of 81679690697 is 79609697618.

It is a cyclic number.

It is not a de Polignac number, because 81679690697 - 2⁴ = 81679690681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81679698697) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3064454 + ... + 3090992.

It is an arithmetic number, because the mean of its divisors is an integer number (5638051440).

Almost surely, 2^81679690697 is an apocalyptic number.

It is an amenable number.

81679690697 is a deficient number, since it is larger than the sum of its proper divisors (8529132343).

81679690697 is a wasteful number, since it uses less digits than its factorization.

81679690697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30004.

The product of its (nonzero) digits is 61725888, while the sum is 68.

The spelling of 81679690697 in words is "eighty-one billion, six hundred seventy-nine million, six hundred ninety thousand, six hundred ninety-seven".