91771840512 has 576 divisors, whose sum is σ = 308390846400. Its totient is φ = 26741145600.

The previous prime is 91771840499. The next prime is 91771840547. The reversal of 91771840512 is 21504817719.

It is a happy number.

91771840512 is a `hidden beast` number, since 91 + 7 + 7 + 1 + 8 + 40 + 512 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 584533938 + ... + 584534094.

It is an arithmetic number, because the mean of its divisors is an integer number (535400775).

Almost surely, 2^91771840512 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91771840512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154195423200).

91771840512 is an abundant number, since it is smaller than the sum of its proper divisors (216619005888).

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

91771840512 is a wasteful number, since it uses less digits than its factorization.

91771840512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261 (or 204 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 45.

The spelling of 91771840512 in words is "ninety-one billion, seven hundred seventy-one million, eight hundred forty thousand, five hundred twelve".