9866408661 has 16 divisors (see below), whose sum is σ = 14625726400. Its totient is φ = 6573634704.

The previous prime is 9866408599. The next prime is 9866408687. The reversal of 9866408661 is 1668046689.

It is not a de Polignac number, because 9866408661 - 2³⁰ = 8792666837 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 9866408598 and 9866408607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9866408561) 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, 64411 + ... + 154536.

It is an arithmetic number, because the mean of its divisors is an integer number (914107900).

Almost surely, 2^9866408661 is an apocalyptic number.

It is an amenable number.

9866408661 is a deficient number, since it is larger than the sum of its proper divisors (4759317739).

9866408661 is a wasteful number, since it uses less digits than its factorization.

9866408661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220625 (or 220619 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 54.

The square root of 9866408661 is about 99329.7974476944. The cubic root of 9866408661 is about 2144.7978546850.

The spelling of 9866408661 in words is "nine billion, eight hundred sixty-six million, four hundred eight thousand, six hundred sixty-one".