91109281 has 4 divisors (see below), whose sum is σ = 93571732. Its totient is φ = 88646832.

The previous prime is 91109267. The next prime is 91109299. The reversal of 91109281 is 18290119.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18290119 = 251 ⋅72869.

It can be written as a sum of positive squares in 2 ways, for example, as 76737600 + 14371681 = 8760^2 + 3791^2 .

It is a cyclic number.

It is not a de Polignac number, because 91109281 - 2⁹ = 91108769 is a prime.

It is a super-2 number, since 2×91109281² = 16601802168673922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91109231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1231170 + ... + 1231243.

It is an arithmetic number, because the mean of its divisors is an integer number (23392933).

Almost surely, 2^91109281 is an apocalyptic number.

It is an amenable number.

91109281 is a deficient number, since it is larger than the sum of its proper divisors (2462451).

91109281 is a wasteful number, since it uses less digits than its factorization.

91109281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2462450.

The product of its (nonzero) digits is 1296, while the sum is 31.

The square root of 91109281 is about 9545.1181763245. The cubic root of 91109281 is about 449.9741236149.

The spelling of 91109281 in words is "ninety-one million, one hundred nine thousand, two hundred eighty-one".