91859172809 has 16 divisors (see below), whose sum is σ = 93766619520. Its totient is φ = 89970353280.

The previous prime is 91859172791. The next prime is 91859172859. The reversal of 91859172809 is 90827195819.

It is a cyclic number.

It is not a de Polignac number, because 91859172809 - 2²⁰ = 91858124233 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91859172859) 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, 14979674 + ... + 14985804.

It is an arithmetic number, because the mean of its divisors is an integer number (5860413720).

Almost surely, 2^91859172809 is an apocalyptic number.

It is an amenable number.

91859172809 is a deficient number, since it is larger than the sum of its proper divisors (1907446711).

91859172809 is a wasteful number, since it uses less digits than its factorization.

91859172809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7600.

The product of its (nonzero) digits is 3265920, while the sum is 59.

The spelling of 91859172809 in words is "ninety-one billion, eight hundred fifty-nine million, one hundred seventy-two thousand, eight hundred nine".