91322731661 has 4 divisors (see below), whose sum is σ = 104368836192. Its totient is φ = 78276627132.

The previous prime is 91322731657. The next prime is 91322731691. The reversal of 91322731661 is 16613722319.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 91322731661 - 2² = 91322731657 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91322731691) 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, 6523052255 + ... + 6523052268.

It is an arithmetic number, because the mean of its divisors is an integer number (26092209048).

Almost surely, 2^91322731661 is an apocalyptic number.

It is an amenable number.

91322731661 is a deficient number, since it is larger than the sum of its proper divisors (13046104531).

91322731661 is a wasteful number, since it uses less digits than its factorization.

91322731661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13046104530.

The product of its digits is 81648, while the sum is 41.

The spelling of 91322731661 in words is "ninety-one billion, three hundred twenty-two million, seven hundred thirty-one thousand, six hundred sixty-one".