91897790400 has 504 divisors, whose sum is σ = 353205403824. Its totient is φ = 22527590400.

The previous prime is 91897790357. The next prime is 91897790417. The reversal of 91897790400 is 409779819.

91897790400 is a `hidden beast` number, since 9 + 1 + 89 + 77 + 90 + 400 = 666.

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 71 ways as a sum of consecutive naturals, for example, 52602327 + ... + 52604073.

Almost surely, 2^91897790400 is an apocalyptic number.

91897790400 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 91897790400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (176602701912).

91897790400 is an abundant number, since it is smaller than the sum of its proper divisors (261307613424).

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

91897790400 is a wasteful number, since it uses less digits than its factorization.

91897790400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2069 (or 2051 counting only the distinct ones).

The product of its (nonzero) digits is 1143072, while the sum is 54.

The spelling of 91897790400 in words is "ninety-one billion, eight hundred ninety-seven million, seven hundred ninety thousand, four hundred".