91821768 has 16 divisors (see below), whose sum is σ = 229554480. Its totient is φ = 30607248.

The previous prime is 91821767. The next prime is 91821781. The reversal of 91821768 is 86712819.

It is not an unprimeable number, because it can be changed into a prime (91821761) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1912930 + ... + 1912977.

It is an arithmetic number, because the mean of its divisors is an integer number (14347155).

Almost surely, 2^91821768 is an apocalyptic number.

It is an amenable number.

91821768 is an abundant number, since it is smaller than the sum of its proper divisors (137732712).

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

91821768 is a wasteful number, since it uses less digits than its factorization.

91821768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3825916 (or 3825912 counting only the distinct ones).

The product of its digits is 48384, while the sum is 42.

The square root of 91821768 is about 9582.3675571333. The cubic root of 91821768 is about 451.1440322788.

The spelling of 91821768 in words is "ninety-one million, eight hundred twenty-one thousand, seven hundred sixty-eight".