91771591849 has 4 divisors (see below), whose sum is σ = 104881819264. Its totient is φ = 78661364436.

The previous prime is 91771591837. The next prime is 91771591871. The reversal of 91771591849 is 94819517719.

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 91771591849 - 2²³ = 91763203241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91771091849) 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, 6555113697 + ... + 6555113710.

It is an arithmetic number, because the mean of its divisors is an integer number (26220454816).

Almost surely, 2^91771591849 is an apocalyptic number.

It is an amenable number.

91771591849 is a deficient number, since it is larger than the sum of its proper divisors (13110227415).

91771591849 is a wasteful number, since it uses less digits than its factorization.

91771591849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13110227414.

The product of its digits is 5715360, while the sum is 61.

The spelling of 91771591849 in words is "ninety-one billion, seven hundred seventy-one million, five hundred ninety-one thousand, eight hundred forty-nine".