91731660 has 96 divisors (see below), whose sum is σ = 274337280. Its totient is φ = 22821888.

The previous prime is 91731649. The next prime is 91731691. The reversal of 91731660 is 6613719.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 141457 + ... + 142103.

It is an arithmetic number, because the mean of its divisors is an integer number (2857680).

Almost surely, 2^91731660 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 91731660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137168640).

91731660 is an abundant number, since it is smaller than the sum of its proper divisors (182605620).

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

91731660 is a wasteful number, since it uses less digits than its factorization.

91731660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 815 (or 813 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 33.

The square root of 91731660 is about 9577.6646422810. The cubic root of 91731660 is about 450.9964093630.

The spelling of 91731660 in words is "ninety-one million, seven hundred thirty-one thousand, six hundred sixty".