9661695521 has 2 divisors, whose sum is σ = 9661695522. Its totient is φ = 9661695520.

The previous prime is 9661695517. The next prime is 9661695557. The reversal of 9661695521 is 1255961669.

It is a happy number.

9661695521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6478479121 + 3183216400 = 80489^2 + 56420^2 .

It is a cyclic number.

It is not a de Polignac number, because 9661695521 - 2² = 9661695517 is a prime.

It is a super-2 number, since 2×9661695521² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 9661695521.

It is not a weakly prime, because it can be changed into another prime (9661691521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4830847760 + 4830847761.

It is an arithmetic number, because the mean of its divisors is an integer number (4830847761).

Almost surely, 2^9661695521 is an apocalyptic number.

It is an amenable number.

9661695521 is a deficient number, since it is larger than the sum of its proper divisors (1).

9661695521 is an equidigital number, since it uses as much as digits as its factorization.

9661695521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 874800, while the sum is 50.

The square root of 9661695521 is about 98293.9241306399. The cubic root of 9661695521 is about 2129.8602861183.

The spelling of 9661695521 in words is "nine billion, six hundred sixty-one million, six hundred ninety-five thousand, five hundred twenty-one".