91099638 has 96 divisors (see below), whose sum is σ = 236500992. Its totient is φ = 24796800.

The previous prime is 91099621. The next prime is 91099691. The reversal of 91099638 is 83699019.

91099638 is a `hidden beast` number, since 9 + 1 + 0 + 9 + 9 + 638 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 91099593 and 91099602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 324058 + ... + 324338.

It is an arithmetic number, because the mean of its divisors is an integer number (2463552).

Almost surely, 2^91099638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91099638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118250496).

91099638 is an abundant number, since it is smaller than the sum of its proper divisors (145401354).

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

91099638 is a wasteful number, since it uses less digits than its factorization.

91099638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410 (or 407 counting only the distinct ones).

The product of its (nonzero) digits is 104976, while the sum is 45.

The square root of 91099638 is about 9544.6130356343. The cubic root of 91099638 is about 449.9582479781.

The spelling of 91099638 in words is "ninety-one million, ninety-nine thousand, six hundred thirty-eight".