91821053688 has 128 divisors (see below), whose sum is σ = 282614814720. Its totient is φ = 24208957440.

The previous prime is 91821053671. The next prime is 91821053689. The reversal of 91821053688 is 88635012819.

It is a super-2 number, since 2×91821053688² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 91821053688.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91821053689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11879281 + ... + 11887007.

It is an arithmetic number, because the mean of its divisors is an integer number (2207928240).

Almost surely, 2^91821053688 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 91821053688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141307407360).

91821053688 is an abundant number, since it is smaller than the sum of its proper divisors (190793761032).

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

91821053688 is a wasteful number, since it uses less digits than its factorization.

91821053688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13197 (or 13193 counting only the distinct ones).

The product of its (nonzero) digits is 829440, while the sum is 51.

The spelling of 91821053688 in words is "ninety-one billion, eight hundred twenty-one million, fifty-three thousand, six hundred eighty-eight".