91311987291 has 8 divisors (see below), whose sum is σ = 139142075904. Its totient is φ = 52178278440.

The previous prime is 91311987271. The next prime is 91311987329. The reversal of 91311987291 is 19278911319.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 91311987291 - 2²⁵ = 91278432859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91311987271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2174094915 + ... + 2174094956.

It is an arithmetic number, because the mean of its divisors is an integer number (17392759488).

Almost surely, 2^91311987291 is an apocalyptic number.

91311987291 is a deficient number, since it is larger than the sum of its proper divisors (47830088613).

91311987291 is a wasteful number, since it uses less digits than its factorization.

91311987291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4348189881.

The product of its digits is 244944, while the sum is 51.

The spelling of 91311987291 in words is "ninety-one billion, three hundred eleven million, nine hundred eighty-seven thousand, two hundred ninety-one".