91238831885 has 4 divisors (see below), whose sum is σ = 109486598268. Its totient is φ = 72991065504.

The previous prime is 91238831881. The next prime is 91238831909. The reversal of 91238831885 is 58813883219.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 46567050436 + 44671781449 = 215794^2 + 211357^2 .

It is a cyclic number.

It is not a de Polignac number, because 91238831885 - 2² = 91238831881 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 91238831885.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91238831881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9123883184 + ... + 9123883193.

It is an arithmetic number, because the mean of its divisors is an integer number (27371649567).

Almost surely, 2^91238831885 is an apocalyptic number.

It is an amenable number.

91238831885 is a deficient number, since it is larger than the sum of its proper divisors (18247766383).

91238831885 is a wasteful number, since it uses less digits than its factorization.

91238831885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18247766382.

The product of its digits is 3317760, while the sum is 56.

The spelling of 91238831885 in words is "ninety-one billion, two hundred thirty-eight million, eight hundred thirty-one thousand, eight hundred eighty-five".