91357728 has 192 divisors, whose sum is σ = 317011968. Its totient is φ = 22302720.

The previous prime is 91357723. The next prime is 91357729. The reversal of 91357728 is 82775319.

It is a super-3 number, since 3×91357728³ (a number of 25 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 91357728.

It is not an unprimeable number, because it can be changed into a prime (91357723) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 125301 + ... + 126027.

It is an arithmetic number, because the mean of its divisors is an integer number (1651104).

Almost surely, 2^91357728 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 91357728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (158505984).

91357728 is an abundant number, since it is smaller than the sum of its proper divisors (225654240).

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

91357728 is a wasteful number, since it uses less digits than its factorization.

91357728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 775 (or 767 counting only the distinct ones).

The product of its digits is 105840, while the sum is 42.

The square root of 91357728 is about 9558.1236652389. The cubic root of 91357728 is about 450.3827656889.

The spelling of 91357728 in words is "ninety-one million, three hundred fifty-seven thousand, seven hundred twenty-eight".