91917866880 has 640 divisors, whose sum is σ = 387297884160. Its totient is φ = 20329574400.

The previous prime is 91917866861. The next prime is 91917866903. The reversal of 91917866880 is 8866871919.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

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 79 ways as a sum of consecutive naturals, for example, 11245195 + ... + 11253365.

It is an arithmetic number, because the mean of its divisors is an integer number (605152944).

Almost surely, 2^91917866880 is an apocalyptic number.

91917866880 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91917866880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (193648942080).

91917866880 is an abundant number, since it is smaller than the sum of its proper divisors (295380017280).

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

91917866880 is a wasteful number, since it uses less digits than its factorization.

91917866880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8240 (or 8219 counting only the distinct ones).

The product of its (nonzero) digits is 10450944, while the sum is 63.

The spelling of 91917866880 in words is "ninety-one billion, nine hundred seventeen million, eight hundred sixty-six thousand, eight hundred eighty".