91078563985 has 12 divisors (see below), whose sum is σ = 110695298868. Its totient is φ = 71940511968.

The previous prime is 91078563959. The next prime is 91078563991. The reversal of 91078563985 is 58936587019.

It can be written as a sum of positive squares in 2 ways, for example, as 68832244881 + 22246319104 = 262359^2 + 149152^2 .

It is a de Polignac number, because none of the positive numbers 2^k-91078563985 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1428154 + ... + 1490563.

It is an arithmetic number, because the mean of its divisors is an integer number (9224608239).

Almost surely, 2^91078563985 is an apocalyptic number.

It is an amenable number.

91078563985 is a deficient number, since it is larger than the sum of its proper divisors (19616734883).

91078563985 is an equidigital number, since it uses as much as digits as its factorization.

91078563985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2918880 (or 2918801 counting only the distinct ones).

The product of its (nonzero) digits is 16329600, while the sum is 61.

The spelling of 91078563985 in words is "ninety-one billion, seventy-eight million, five hundred sixty-three thousand, nine hundred eighty-five".