91333728 has 72 divisors (see below), whose sum is σ = 260828568. Its totient is φ = 30316032.

The previous prime is 91333727. The next prime is 91333729. The reversal of 91333728 is 82733319.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (91333727) and next prime (91333729).

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 91333692 and 91333701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91333721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 87900 + ... + 88932.

It is an arithmetic number, because the mean of its divisors is an integer number (3622619).

Almost surely, 2^91333728 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 91333728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130414284).

91333728 is an abundant number, since it is smaller than the sum of its proper divisors (169494840).

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

91333728 is a wasteful number, since it uses less digits than its factorization.

91333728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1356 (or 1345 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

The square root of 91333728 is about 9556.8681062365. The cubic root of 91333728 is about 450.3433231834.

The spelling of 91333728 in words is "ninety-one million, three hundred thirty-three thousand, seven hundred twenty-eight".