91039909 has 2 divisors, whose sum is σ = 91039910. Its totient is φ = 91039908.

The previous prime is 91039873. The next prime is 91039931. The reversal of 91039909 is 90993019.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46444225 + 44595684 = 6815^2 + 6678^2 .

It is a cyclic number.

It is not a de Polignac number, because 91039909 - 2¹¹ = 91037861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91039309) 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 as a sum of consecutive naturals, namely, 45519954 + 45519955.

It is an arithmetic number, because the mean of its divisors is an integer number (45519955).

Almost surely, 2^91039909 is an apocalyptic number.

It is an amenable number.

91039909 is a deficient number, since it is larger than the sum of its proper divisors (1).

91039909 is an equidigital number, since it uses as much as digits as its factorization.

91039909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19683, while the sum is 40.

The square root of 91039909 is about 9541.4835848520. The cubic root of 91039909 is about 449.8598888901.

The spelling of 91039909 in words is "ninety-one million, thirty-nine thousand, nine hundred nine".