91439009 has 2 divisors, whose sum is σ = 91439010. Its totient is φ = 91439008.

The previous prime is 91438999. The next prime is 91439063. The reversal of 91439009 is 90093419.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79210000 + 12229009 = 8900^2 + 3497^2 .

It is a cyclic number.

It is not a de Polignac number, because 91439009 - 2⁴ = 91438993 is a prime.

It is a super-2 number, since 2×91439009² = 16722184733804162, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 91439009.

It is not a weakly prime, because it can be changed into another prime (91439069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45719504 + 45719505.

It is an arithmetic number, because the mean of its divisors is an integer number (45719505).

Almost surely, 2^91439009 is an apocalyptic number.

It is an amenable number.

91439009 is a deficient number, since it is larger than the sum of its proper divisors (1).

91439009 is an equidigital number, since it uses as much as digits as its factorization.

91439009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8748, while the sum is 35.

The square root of 91439009 is about 9562.3746527732. The cubic root of 91439009 is about 450.5162946603.

The spelling of 91439009 in words is "ninety-one million, four hundred thirty-nine thousand, nine".