91991160 has 128 divisors (see below), whose sum is σ = 322848000. Its totient is φ = 23234688.

The previous prime is 91991117. The next prime is 91991171. The reversal of 91991160 is 6119919.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18279 + ... + 22761.

It is an arithmetic number, because the mean of its divisors is an integer number (2522250).

Almost surely, 2^91991160 is an apocalyptic number.

91991160 is a gapful number since it is divisible by the number (90) 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 91991160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (161424000).

91991160 is an abundant number, since it is smaller than the sum of its proper divisors (230856840).

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

91991160 is a wasteful number, since it uses less digits than its factorization.

With its successor (91991161) it forms an eRAP, since the sums of their prime factors are consecutive (4522 and 4523).

91991160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4522 (or 4512 counting only the distinct ones).

The product of its (nonzero) digits is 4374, while the sum is 36.

The square root of 91991160 is about 9591.2022187002. The cubic root of 91991160 is about 451.4212840554.

The spelling of 91991160 in words is "ninety-one million, nine hundred ninety-one thousand, one hundred sixty".