81193161611 has 4 divisors (see below), whose sum is σ = 82404999912. Its totient is φ = 79981323312.

The previous prime is 81193161523. The next prime is 81193161671. The reversal of 81193161611 is 11616139118.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81193161611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81193161671) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 605919050 + ... + 605919183.

It is an arithmetic number, because the mean of its divisors is an integer number (20601249978).

Almost surely, 2^81193161611 is an apocalyptic number.

81193161611 is a deficient number, since it is larger than the sum of its proper divisors (1211838301).

81193161611 is a wasteful number, since it uses less digits than its factorization.

81193161611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1211838300.

The product of its digits is 7776, while the sum is 38.

The spelling of 81193161611 in words is "eighty-one billion, one hundred ninety-three million, one hundred sixty-one thousand, six hundred eleven".