91223803728 has 120 divisors (see below), whose sum is σ = 266710197312. Its totient is φ = 29051979264.

The previous prime is 91223803721. The next prime is 91223803729. The reversal of 91223803728 is 82730832219.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91223803721) 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 23 ways as a sum of consecutive naturals, for example, 2908900 + ... + 2940092.

Almost surely, 2^91223803728 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 91223803728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133355098656).

91223803728 is an abundant number, since it is smaller than the sum of its proper divisors (175486393584).

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

91223803728 is a wasteful number, since it uses less digits than its factorization.

91223803728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32113 (or 32104 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The spelling of 91223803728 in words is "ninety-one billion, two hundred twenty-three million, eight hundred three thousand, seven hundred twenty-eight".