91999040 has 112 divisors (see below), whose sum is σ = 254520192. Its totient is φ = 31021056.

The previous prime is 91999027. The next prime is 91999051. The reversal of 91999040 is 4099919.

It is a tau number, because it is divible by the number of its divisors (112).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 149774 + ... + 150386.

Almost surely, 2^91999040 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 91999040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127260096).

91999040 is an abundant number, since it is smaller than the sum of its proper divisors (162521152).

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

91999040 is a wasteful number, since it uses less digits than its factorization.

91999040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 704 (or 694 counting only the distinct ones).

The product of its (nonzero) digits is 26244, while the sum is 41.

The square root of 91999040 is about 9591.6130030355. The cubic root of 91999040 is about 451.4341733307.

The spelling of 91999040 in words is "ninety-one million, nine hundred ninety-nine thousand, forty".