91605556800 has 672 divisors, whose sum is σ = 345871434240. Its totient is φ = 23865477120.

The previous prime is 91605556759. The next prime is 91605556871. The reversal of 91605556800 is 865550619.

It is a happy number.

91605556800 is a `hidden beast` number, since 9 + 16 + 0 + 5 + 556 + 80 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 164462122 + ... + 164462678.

Almost surely, 2^91605556800 is an apocalyptic number.

91605556800 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 91605556800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (172935717120).

91605556800 is an abundant number, since it is smaller than the sum of its proper divisors (254265877440).

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

91605556800 is an equidigital number, since it uses as much as digits as its factorization.

91605556800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 647 (or 614 counting only the distinct ones).

The product of its (nonzero) digits is 324000, while the sum is 45.

The spelling of 91605556800 in words is "ninety-one billion, six hundred five million, five hundred fifty-six thousand, eight hundred".