91256909 has 4 divisors (see below), whose sum is σ = 91304604. Its totient is φ = 91209216.

The previous prime is 91256899. The next prime is 91256927. The reversal of 91256909 is 90965219.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90965219 = 839 ⋅108421.

It can be written as a sum of positive squares in 2 ways, for example, as 13764100 + 77492809 = 3710^2 + 8803^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91256909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91256989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20852 + ... + 24845.

It is an arithmetic number, because the mean of its divisors is an integer number (22826151).

Almost surely, 2^91256909 is an apocalyptic number.

It is an amenable number.

91256909 is a deficient number, since it is larger than the sum of its proper divisors (47695).

91256909 is a wasteful number, since it uses less digits than its factorization.

91256909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47694.

The product of its (nonzero) digits is 43740, while the sum is 41.

The square root of 91256909 is about 9552.8482140145. The cubic root of 91256909 is about 450.2170294689.

The spelling of 91256909 in words is "ninety-one million, two hundred fifty-six thousand, nine hundred nine".