9999660321800 has 108 divisors (see below), whose sum is σ = 24026708527335. Its totient is φ = 3870299606400.

The previous prime is 9999660321793. The next prime is 9999660321809. The reversal of 9999660321800 is 81230669999.

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 5 ways, for example, as 7096650914116 + 2903009407684 = 2663954^2 + 1703822^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=2236030.

It is a Harshad number since it is a multiple of its sum of digits (62).

It is not an unprimeable number, because it can be changed into a prime (9999660321809) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1386334994 + ... + 1386342206.

Almost surely, 2^{9999660321800} 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 9999660321800

9999660321800 is an abundant number, since it is smaller than the sum of its proper divisors (14027048205535).

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

9999660321800 is an frugal number, since it uses more digits than its factorization.

9999660321800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14504 (or 7251 counting only the distinct ones).

The product of its (nonzero) digits is 11337408, while the sum is 62.

The spelling of 9999660321800 in words is "nine trillion, nine hundred ninety-nine billion, six hundred sixty million, three hundred twenty-one thousand, eight hundred".