9661564399 has 2 divisors, whose sum is σ = 9661564400. Its totient is φ = 9661564398.

The previous prime is 9661564387. The next prime is 9661564403. The reversal of 9661564399 is 9934651669.

It is a strong prime.

It is an emirp because it is prime and its reverse (9934651669) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9661564399 - 2¹³ = 9661556207 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9661564699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4830782199 + 4830782200.

It is an arithmetic number, because the mean of its divisors is an integer number (4830782200).

Almost surely, 2^9661564399 is an apocalyptic number.

9661564399 is a deficient number, since it is larger than the sum of its proper divisors (1).

9661564399 is an equidigital number, since it uses as much as digits as its factorization.

9661564399 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9447840, while the sum is 58.

The square root of 9661564399 is about 98293.2571390327. The cubic root of 9661564399 is about 2129.8506510667.

The spelling of 9661564399 in words is "nine billion, six hundred sixty-one million, five hundred sixty-four thousand, three hundred ninety-nine".