9571996661 has 4 divisors (see below), whose sum is σ = 9575104512. Its totient is φ = 9568888812.

The previous prime is 9571996649. The next prime is 9571996699. The reversal of 9571996661 is 1666991759.

9571996661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1666991759 = 193 ⋅8637263.

It is a cyclic number.

It is not a de Polignac number, because 9571996661 - 2¹⁰ = 9571995637 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 9571996661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9571996631) 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 in 3 ways as a sum of consecutive naturals, for example, 1549301 + ... + 1555466.

It is an arithmetic number, because the mean of its divisors is an integer number (2393776128).

Almost surely, 2^9571996661 is an apocalyptic number.

It is an amenable number.

9571996661 is a deficient number, since it is larger than the sum of its proper divisors (3107851).

9571996661 is a wasteful number, since it uses less digits than its factorization.

9571996661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3107850.

The product of its digits is 5511240, while the sum is 59.

The square root of 9571996661 is about 97836.5814049121. The cubic root of 9571996661 is about 2123.2485987844.

The spelling of 9571996661 in words is "nine billion, five hundred seventy-one million, nine hundred ninety-six thousand, six hundred sixty-one".