9661564865 has 16 divisors (see below), whose sum is σ = 12561360768. Its totient is φ = 7105410816.

The previous prime is 9661564841. The next prime is 9661564867. The reversal of 9661564865 is 5684651669.

It is a happy number.

It is not a de Polignac number, because 9661564865 - 2⁸ = 9661564609 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 9661564865.

It is not an unprimeable number, because it can be changed into a prime (9661564867) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1318037 + ... + 1325346.

It is an arithmetic number, because the mean of its divisors is an integer number (785085048).

Almost surely, 2^9661564865 is an apocalyptic number.

It is an amenable number.

9661564865 is a deficient number, since it is larger than the sum of its proper divisors (2899795903).

9661564865 is a wasteful number, since it uses less digits than its factorization.

9661564865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2643448.

The product of its digits is 9331200, while the sum is 56.

The square root of 9661564865 is about 98293.2595094903. The cubic root of 9661564865 is about 2129.8506853093.

The spelling of 9661564865 in words is "nine billion, six hundred sixty-one million, five hundred sixty-four thousand, eight hundred sixty-five".