91128438 has 48 divisors (see below), whose sum is σ = 210862080. Its totient is φ = 28374192.

The previous prime is 91128431. The next prime is 91128451. The reversal of 91128438 is 83482119.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91128431) 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, 15243 + ... + 20361.

It is an arithmetic number, because the mean of its divisors is an integer number (4392960).

Almost surely, 2^91128438 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91128438, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105431040).

91128438 is an abundant number, since it is smaller than the sum of its proper divisors (119733642).

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

91128438 is a wasteful number, since it uses less digits than its factorization.

91128438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5193 (or 5190 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 91128438 is about 9546.1216208469. The cubic root of 91128438 is about 450.0056591881.

The spelling of 91128438 in words is "ninety-one million, one hundred twenty-eight thousand, four hundred thirty-eight".