91723309 has 2 divisors, whose sum is σ = 91723310. Its totient is φ = 91723308.

The previous prime is 91723301. The next prime is 91723339. The reversal of 91723309 is 90332719.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48860100 + 42863209 = 6990^2 + 6547^2 .

It is an emirp because it is prime and its reverse (90332719) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91723309 - 2³ = 91723301 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91723301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45861654 + 45861655.

It is an arithmetic number, because the mean of its divisors is an integer number (45861655).

Almost surely, 2^91723309 is an apocalyptic number.

It is an amenable number.

91723309 is a deficient number, since it is larger than the sum of its proper divisors (1).

91723309 is an equidigital number, since it uses as much as digits as its factorization.

91723309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10206, while the sum is 34.

The square root of 91723309 is about 9577.2286701321. The cubic root of 91723309 is about 450.9827231203.

The spelling of 91723309 in words is "ninety-one million, seven hundred twenty-three thousand, three hundred nine".