9661665408 has 64 divisors (see below), whose sum is σ = 25836192000. Its totient is φ = 3198921728.

The previous prime is 9661665379. The next prime is 9661665443. The reversal of 9661665408 is 8045661669.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×9661665408² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (51) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27216 + ... + 141647.

It is an arithmetic number, because the mean of its divisors is an integer number (403690500).

Almost surely, 2^9661665408 is an apocalyptic number.

It is an amenable number.

9661665408 is an abundant number, since it is smaller than the sum of its proper divisors (16174526592).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9661665408 is a wasteful number, since it uses less digits than its factorization.

9661665408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169029 (or 169017 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 51.

The square root of 9661665408 is about 98293.7709521819. The cubic root of 9661665408 is about 2129.8580733752.

The spelling of 9661665408 in words is "nine billion, six hundred sixty-one million, six hundred sixty-five thousand, four hundred eight".