91383728656 has 80 divisors (see below), whose sum is σ = 198955266048. Its totient is φ = 40302864000.

The previous prime is 91383728641. The next prime is 91383728729. The reversal of 91383728656 is 65682738319.

It is a self number, because there is not a number n which added to its sum of digits gives 91383728656.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1102785 + ... + 1182751.

Almost surely, 2^91383728656 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 91383728656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99477633024).

91383728656 is an abundant number, since it is smaller than the sum of its proper divisors (107571537392).

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

91383728656 is a wasteful number, since it uses less digits than its factorization.

91383728656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80180 (or 80174 counting only the distinct ones).

The product of its digits is 13063680, while the sum is 58.

The spelling of 91383728656 in words is "ninety-one billion, three hundred eighty-three million, seven hundred twenty-eight thousand, six hundred fifty-six".