9965561628672 has 384 divisors, whose sum is σ = 31979683008000. Its totient is φ = 3066289274880.

The previous prime is 9965561628643. The next prime is 9965561628683. The reversal of 9965561628672 is 2768261655699.

It is a happy number.

9965561628672 is a `hidden beast` number, since 9 + 9 + 6 + 556 + 1 + 6 + 2 + 8 + 67 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a self number, because there is not a number n which added to its sum of digits gives 9965561628672.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 121444297 + ... + 121526327.

It is an arithmetic number, because the mean of its divisors is an integer number (83280424500).

Almost surely, 2^{9965561628672} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9965561628672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15989841504000).

9965561628672 is an abundant number, since it is smaller than the sum of its proper divisors (22014121379328).

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

9965561628672 is an equidigital number, since it uses as much as digits as its factorization.

9965561628672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82101 (or 82049 counting only the distinct ones).

The product of its digits is 587865600, while the sum is 72.

The spelling of 9965561628672 in words is "nine trillion, nine hundred sixty-five billion, five hundred sixty-one million, six hundred twenty-eight thousand, six hundred seventy-two".