91561400 has 72 divisors (see below), whose sum is σ = 247662720. Its totient is φ = 31389120.

The previous prime is 91561397. The next prime is 91561403. The reversal of 91561400 is 416519.

It is an interprime number because it is at equal distance from previous prime (91561397) and next prime (91561403).

It is a self number, because there is not a number n which added to its sum of digits gives 91561400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91561403) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 5129 + ... + 14471.

It is an arithmetic number, because the mean of its divisors is an integer number (3439760).

Almost surely, 2^91561400 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 91561400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123831360).

91561400 is an abundant number, since it is smaller than the sum of its proper divisors (156101320).

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

91561400 is a wasteful number, since it uses less digits than its factorization.

91561400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9373 (or 9357 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 91561400 is about 9568.7721260358. The cubic root of 91561400 is about 450.7172102122.

Adding to 91561400 its reverse (416519), we get a palindrome (91977919).

The spelling of 91561400 in words is "ninety-one million, five hundred sixty-one thousand, four hundred".