9999785539872 has 486 divisors, whose sum is σ = 30795182199873. Its totient is φ = 3077368971264.

The previous prime is 9999785539859. The next prime is 9999785539879. The reversal of 9999785539872 is 2789355879999.

It is a happy number.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 14 ways, for example, as 1573328696976 + 8426456842896 = 1254324^2 + 2902836^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=2236044.

It is not an unprimeable number, because it can be changed into a prime (9999785539879) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 88493677288 + ... + 88493677400.

Almost surely, 2^{9999785539872} 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 9999785539872

9999785539872 is an abundant number, since it is smaller than the sum of its proper divisors (20795396660001).

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

9999785539872 is a wasteful number, since it uses less digits than its factorization.

9999785539872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 470 (or 232 counting only the distinct ones).

The product of its digits is 27776649600, while the sum is 90.

The spelling of 9999785539872 in words is "nine trillion, nine hundred ninety-nine billion, seven hundred eighty-five million, five hundred thirty-nine thousand, eight hundred seventy-two".