9611985661 has 4 divisors (see below), whose sum is σ = 9612696924. Its totient is φ = 9611274400.

The previous prime is 9611985641. The next prime is 9611985667. The reversal of 9611985661 is 1665891169.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8316345636 + 1295640025 = 91194^2 + 35995^2 .

It is a cyclic number.

It is not a de Polignac number, because 9611985661 - 2²³ = 9603597053 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 9611985599 and 9611985608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9611985667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 334960 + ... + 362521.

It is an arithmetic number, because the mean of its divisors is an integer number (2403174231).

Almost surely, 2^9611985661 is an apocalyptic number.

It is an amenable number.

9611985661 is a deficient number, since it is larger than the sum of its proper divisors (711263).

9611985661 is a wasteful number, since it uses less digits than its factorization.

9611985661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 711262.

The product of its digits is 699840, while the sum is 52.

The square root of 9611985661 is about 98040.7347024695. The cubic root of 9611985661 is about 2126.2012611736.

The spelling of 9611985661 in words is "nine billion, six hundred eleven million, nine hundred eighty-five thousand, six hundred sixty-one".