91581216 has 192 divisors, whose sum is σ = 275788800. Its totient is φ = 26459136.

The previous prime is 91581209. The next prime is 91581229. The reversal of 91581216 is 61218519.

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 1552195 + ... + 1552253.

It is an arithmetic number, because the mean of its divisors is an integer number (1436400).

Almost surely, 2^91581216 is an apocalyptic number.

91581216 is a gapful number since it is divisible by the number (96) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91581216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137894400).

91581216 is an abundant number, since it is smaller than the sum of its proper divisors (184207584).

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

91581216 is a wasteful number, since it uses less digits than its factorization.

91581216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151 (or 143 counting only the distinct ones).

The product of its digits is 4320, while the sum is 33.

The square root of 91581216 is about 9569.8075215753. The cubic root of 91581216 is about 450.7497230688.

The spelling of 91581216 in words is "ninety-one million, five hundred eighty-one thousand, two hundred sixteen".