91491800400 has 2700 divisors, whose sum is σ = 465764010624. Its totient is φ = 16982784000.

The previous prime is 91491800383. The next prime is 91491800417. The reversal of 91491800400 is 400819419.

91491800400 is a `hidden beast` number, since 91 + 4 + 91 + 80 + 0 + 400 = 666.

It is an interprime number because it is at equal distance from previous prime (91491800383) and next prime (91491800417).

It is a tau number, because it is divible by the number of its divisors (2700).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 539 ways as a sum of consecutive naturals, for example, 2951348385 + ... + 2951348415.

Almost surely, 2^91491800400 is an apocalyptic number.

91491800400 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 91491800400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (232882005312).

91491800400 is an abundant number, since it is smaller than the sum of its proper divisors (374272210224).

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

91491800400 is a wasteful number, since it uses less digits than its factorization.

91491800400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112 (or 72 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The spelling of 91491800400 in words is "ninety-one billion, four hundred ninety-one million, eight hundred thousand, four hundred".