91009523 has 4 divisors (see below), whose sum is σ = 99283128. Its totient is φ = 82735920.

The previous prime is 91009493. The next prime is 91009547. The reversal of 91009523 is 32590019.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 91009523 - 2¹² = 91005427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91009123) 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, 4136786 + ... + 4136807.

It is an arithmetic number, because the mean of its divisors is an integer number (24820782).

Almost surely, 2^91009523 is an apocalyptic number.

91009523 is a deficient number, since it is larger than the sum of its proper divisors (8273605).

91009523 is a wasteful number, since it uses less digits than its factorization.

91009523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8273604.

The product of its (nonzero) digits is 2430, while the sum is 29.

The square root of 91009523 is about 9539.8911419366. The cubic root of 91009523 is about 449.8098340522.

The spelling of 91009523 in words is "ninety-one million, nine thousand, five hundred twenty-three".