91555998720 has 176 divisors, whose sum is σ = 293183916768. Its totient is φ = 24385945600.

The previous prime is 91555998713. The next prime is 91555998727. The reversal of 91555998720 is 2789955519.

It is an interprime number because it is at equal distance from previous prime (91555998713) and next prime (91555998727).

It is a Harshad number since it is a multiple of its sum of digits (60).

It is not an unprimeable number, because it can be changed into a prime (91555998727) 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 15 ways as a sum of consecutive naturals, for example, 15003670 + ... + 15009770.

Almost surely, 2^91555998720 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 91555998720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (146591958384).

91555998720 is an abundant number, since it is smaller than the sum of its proper divisors (201627918048).

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

91555998720 is a wasteful number, since it uses less digits than its factorization.

91555998720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7106 (or 7088 counting only the distinct ones).

The product of its (nonzero) digits is 10206000, while the sum is 60.

The spelling of 91555998720 in words is "ninety-one billion, five hundred fifty-five million, nine hundred ninety-eight thousand, seven hundred twenty".