91564609 has 2 divisors, whose sum is σ = 91564610. Its totient is φ = 91564608.

The previous prime is 91564589. The next prime is 91564639. The reversal of 91564609 is 90646519.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78712384 + 12852225 = 8872^2 + 3585^2 .

It is a cyclic number.

It is not a de Polignac number, because 91564609 - 2⁷ = 91564481 is a prime.

It is not a weakly prime, because it can be changed into another prime (91564639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45782304 + 45782305.

It is an arithmetic number, because the mean of its divisors is an integer number (45782305).

Almost surely, 2^91564609 is an apocalyptic number.

It is an amenable number.

91564609 is a deficient number, since it is larger than the sum of its proper divisors (1).

91564609 is an equidigital number, since it uses as much as digits as its factorization.

91564609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 58320, while the sum is 40.

The square root of 91564609 is about 9568.9398054330. The cubic root of 91564609 is about 450.7224756575.

The spelling of 91564609 in words is "ninety-one million, five hundred sixty-four thousand, six hundred nine".