91310509 has 2 divisors, whose sum is σ = 91310510. Its totient is φ = 91310508.

The previous prime is 91310459. The next prime is 91310563. The reversal of 91310509 is 90501319.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53978409 + 37332100 = 7347^2 + 6110^2 .

It is a cyclic number.

It is not a de Polignac number, because 91310509 - 2⁹ = 91309997 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91350509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45655254 + 45655255.

It is an arithmetic number, because the mean of its divisors is an integer number (45655255).

Almost surely, 2^91310509 is an apocalyptic number.

It is an amenable number.

91310509 is a deficient number, since it is larger than the sum of its proper divisors (1).

91310509 is an equidigital number, since it uses as much as digits as its factorization.

91310509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1215, while the sum is 28.

The square root of 91310509 is about 9555.6532482086. The cubic root of 91310509 is about 450.3051576263.

It can be divided in two parts, 91310 and 509, that added together give a palindrome (91819).

The spelling of 91310509 in words is "ninety-one million, three hundred ten thousand, five hundred nine".