91128969 has 20 divisors (see below), whose sum is σ = 137671380. Its totient is φ = 60065280.

The previous prime is 91128943. The next prime is 91129021. The reversal of 91128969 is 96982119.

It can be written as a sum of positive squares in 2 ways, for example, as 4862025 + 86266944 = 2205^2 + 9288^2 .

It is not a de Polignac number, because 91128969 - 2⁷ = 91128841 is a prime.

It is a super-2 number, since 2×91128969² = 16608977982005922, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (91128929) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 889 + ... + 13529.

It is an arithmetic number, because the mean of its divisors is an integer number (6883569).

Almost surely, 2^91128969 is an apocalyptic number.

It is an amenable number.

91128969 is a deficient number, since it is larger than the sum of its proper divisors (46542411).

91128969 is a wasteful number, since it uses less digits than its factorization.

91128969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12742 (or 12733 counting only the distinct ones).

The product of its digits is 69984, while the sum is 45.

The square root of 91128969 is about 9546.1494331484. The cubic root of 91128969 is about 450.0065332385.

It can be divided in two parts, 9112 and 8969, that added together give a palindrome (18081).

The spelling of 91128969 in words is "ninety-one million, one hundred twenty-eight thousand, nine hundred sixty-nine".