91170381978 has 32 divisors (see below), whose sum is σ = 218185531200. Its totient is φ = 28052425008.

The previous prime is 91170381959. The next prime is 91170381989. The reversal of 91170381978 is 87918307119.

91170381978 is a `hidden beast` number, since 9 + 1 + 170 + 381 + 97 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 64935468 + ... + 64936871.

It is an arithmetic number, because the mean of its divisors is an integer number (6818297850).

Almost surely, 2^91170381978 is an apocalyptic number.

91170381978 is an abundant number, since it is smaller than the sum of its proper divisors (127015149222).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91170381978 is a wasteful number, since it uses less digits than its factorization.

91170381978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129872363 (or 129872357 counting only the distinct ones).

The product of its (nonzero) digits is 762048, while the sum is 54.

The spelling of 91170381978 in words is "ninety-one billion, one hundred seventy million, three hundred eighty-one thousand, nine hundred seventy-eight".