91559609 has 2 divisors, whose sum is σ = 91559610. Its totient is φ = 91559608.

The previous prime is 91559549. The next prime is 91559621. The reversal of 91559609 is 90695519.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 84695209 + 6864400 = 9203^2 + 2620^2 .

It is an emirp because it is prime and its reverse (90695519) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91559609 - 2²⁰ = 90511033 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91559609.

It is not a weakly prime, because it can be changed into another prime (91559659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45779804 + 45779805.

It is an arithmetic number, because the mean of its divisors is an integer number (45779805).

Almost surely, 2^91559609 is an apocalyptic number.

It is an amenable number.

91559609 is a deficient number, since it is larger than the sum of its proper divisors (1).

91559609 is an equidigital number, since it uses as much as digits as its factorization.

91559609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 109350, while the sum is 44.

The square root of 91559609 is about 9568.6785399030. The cubic root of 91559609 is about 450.7142714200.

The spelling of 91559609 in words is "ninety-one million, five hundred fifty-nine thousand, six hundred nine".