91868542085 has 4 divisors (see below), whose sum is σ = 110242250508. Its totient is φ = 73494833664.

The previous prime is 91868542063. The next prime is 91868542093. The reversal of 91868542085 is 58024586819.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58024586819 = 47 ⋅1234565677.

It can be written as a sum of positive squares in 2 ways, for example, as 12740539876 + 79128002209 = 112874^2 + 281297^2 .

It is a cyclic number.

It is not a de Polignac number, because 91868542085 - 2¹⁶ = 91868476549 is a prime.

It is a super-2 number, since 2×91868542085² (a number of 23 digits) contains 22 as substring.

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 91868542085.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9186854204 + ... + 9186854213.

It is an arithmetic number, because the mean of its divisors is an integer number (27560562627).

Almost surely, 2^91868542085 is an apocalyptic number.

It is an amenable number.

91868542085 is a deficient number, since it is larger than the sum of its proper divisors (18373708423).

91868542085 is a wasteful number, since it uses less digits than its factorization.

91868542085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18373708422.

The product of its (nonzero) digits is 5529600, while the sum is 56.

The spelling of 91868542085 in words is "ninety-one billion, eight hundred sixty-eight million, five hundred forty-two thousand, eighty-five".