91099872 has 144 divisors (see below), whose sum is σ = 286584480. Its totient is φ = 27303936.

The previous prime is 91099871. The next prime is 91099873. The reversal of 91099872 is 27899019.

It is an interprime number because it is at equal distance from previous prime (91099871) and next prime (91099873).

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91099871) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 112204 + ... + 113012.

It is an arithmetic number, because the mean of its divisors is an integer number (1990170).

Almost surely, 2^91099872 is an apocalyptic number.

91099872 is a gapful number since it is divisible by the number (92) 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 91099872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143292240).

91099872 is an abundant number, since it is smaller than the sum of its proper divisors (195484608).

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

91099872 is a wasteful number, since it uses less digits than its factorization.

91099872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 865 (or 854 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The square root of 91099872 is about 9544.6252938499. The cubic root of 91099872 is about 449.9586332345.

It can be divided in two parts, 9109 and 9872, that added together give a palindrome (18981).

The spelling of 91099872 in words is "ninety-one million, ninety-nine thousand, eight hundred seventy-two".