91791728 has 80 divisors (see below), whose sum is σ = 214272000. Its totient is φ = 37261056.

The previous prime is 91791719. The next prime is 91791751. The reversal of 91791728 is 82719719.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 191393 + ... + 191871.

It is an arithmetic number, because the mean of its divisors is an integer number (2678400).

Almost surely, 2^91791728 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 91791728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107136000).

91791728 is an abundant number, since it is smaller than the sum of its proper divisors (122480272).

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

91791728 is a wasteful number, since it uses less digits than its factorization.

91791728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 582 (or 576 counting only the distinct ones).

The product of its digits is 63504, while the sum is 44.

The square root of 91791728 is about 9580.7999665999. The cubic root of 91791728 is about 451.0948288230.

The spelling of 91791728 in words is "ninety-one million, seven hundred ninety-one thousand, seven hundred twenty-eight".